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From Flowcharts to Python

2

This Activity Workbook introduces students who already know flowchart fundamentals to the

Python Programming language.

The materials in this booklet were developed to help students collaborate with each other in the

learning process and to become self-learners in an active learning environment. Students learn

programming concepts by doing programming and reflecting on the results of the activities that they

engage in.

Author: Lisa M. Olivieri, SSJ, Ph.D.

Name: _______________________________________ Partners: ________________________________ Python Activity 1: Flowcharts and Python

What is the relationship between a flowchart and a Python program?

Critical Thinking Questions:

1. What does the line of Python code in the Python program do? _________________________________________________________________________________

_________________________________________________________________________________

2. Circle equivalent representation of the Python code in the flowchart.

3. Execute following code. What output is produced?

a. print(Hello, my name is Pat!) ________________________________

b. print(Hello, my name is Pat) ________________________________

c. print(Hello.\nMy name is Pat) ________________________________

Learning Objectives

Students will be able to:

Content:

Explain how to display data in Python

Explain how to create a comment in Python

Determine the difference between a string literal and a number Process:

Create print statements in Python

Create Python code that displays results to calculated addition facts

Discuss problems and programs with all group members

Prior Knowledge

Understanding of flowchart output symbols

Further Reading

Transitioning from Visual Logic to Python: Chapter 1

Python Program Flowchart

Python Activity 1: Flowcharts and Python

4

4. Was there a problem with any of the sample code in question 3? If so, what caused the problem? ______________________________________________________________________________

______________________________________________________________________________

5. What caused the different output format for samples a and c in question 3? ______________________________________________________________________________

______________________________________________________________________________

6. What do you think the following Python statements output?

a. print(2+5) _________________________

b. print(2*5) _________________________

c. print(2+5) _________________________

d. print(Age:,20) _________________________

Enter the statements in the Python interpreter to verify your answers.

7. Examine the output for each statement in question 6. a. What is the difference in the output for the statements in a and c of question 6?

______________________________________________________________________________

b. What caused the difference? ____________________________________________________

______________________________________________________________________________

c. Which statements contain a string literal? ______________________________________________________________________________

______________________________________________________________________________

d. What does the comma (,) do in the print statement in part d of question 6? How does it affect the spacing of the output?

______________________________________________________________________________

______________________________________________________________________________

8. Examine the following code and its output. What do the first three lines of the program do?

______________________________________________________________________________

______________________________________________________________________________

Output


5

9. What would happen if you placed a # in front of the code: in the previous program?

______________________________________________________________________________

______________________________________________________________________________

Application Questions: Use the Python interpreter to design and check your work

1. Create a Python program containing three statements to implement the flowchart on the first page of this activity. Write the statements below.

2. Create one Python statement to produce the output expected from the flowchart. Be sure the output is printed on three lines.

3. Create a Python program containing two statements that prints the output to the right. Have the program calculate the answers to the two

arithmetic problems.


6

Notes and Questions Make note of any questions you have about Activity 1 on this page.

Name: _______________________________________ Partners: ________________________________ Python Activity 2: Input and Variables in Python How do you input and store data in a Python program?


1. Enter and execute the Python program. What is printed on the screen when the Python program is executed?

_________________________________________________________________________________

_________________________________________________________________________________

FYI: input() and print() are functions in Python.

2. Draw a line between each flowchart symbol and its corresponding Python code.

Learning Objectives


Content:

Explain how to input data in Python

Explain the meaning and purpose of a variable

Determine if a variable name is valid

Explain concatenation and the use of + Process:

Create input statements in Python

Create Python code that prompts the user for data and stores it in a variable

Create valid and good variable names

Prior Knowledge

Understanding of flowchart input symbols

Further Reading


Python Program

Flowchart Program

Python Activity 2: Input and Variables in Python

8

3. Examine the first line of Python program: name = input(What is your name? )

a. What happens when this line of code is executed?

______________________________________________________________________________

b. What appears on the screen when this line of code is executed?

______________________________________________________________________________

FYI: The words that appear on the screen to tell the user what to enter are known as a prompt.

c. What happens to the data when the user enters their name and presses the Enter button? That is,

where is their name stored?

______________________________________________________________________________

4. What happens when you execute each of the following lines of Python code?

a. name? = input(What is your name?)

______________________________________________________________________________

______________________________________________________________________________

b. your name = input(What is your name?)

______________________________________________________________________________

______________________________________________________________________________

c. 1st_name = input(What is your name?)

______________________________________________________________________________

______________________________________________________________________________

d. from = input(Where were you born?)

______________________________________________________________________________

______________________________________________________________________________

5. Examine the errors that occurred when executing the lines of code in question 5. Then examine the

following lines of valid code.

name2 = input(What is your name?) your_name = input(What is your name?)

yourName = input(What is your name?)

List the rules that need to be followed to create a valid variable name.

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

FYI: The word name in the Python code is a variable name given to a memory location used to store data.


9

6. Are the following variable names valid? Are they good names? Why or why not?

7. Execute the following lines of code. Is the output what you would expect? Why or why not?

_________________________________________________________________________________

_________________________________________________________________________________

8. Use the following set of Python statements to answer the questions below.

a. State the output for each of line of code.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

b. Examine the first two print statements. How are they different? Does the difference affect the

output?

_________________________________________________________________________________

_________________________________________________________________________________

c. Notice that some statements include a comma (,) between the two literals being printed and some

statements use a +. Do they produce the same output? ____________________

d. Explain the purpose of the comma.

_________________________________________________________________________________

_________________________________________________________________________________

e. Why does the last print statement crash the program? What would you do to correct it?

_________________________________________________________________________________

_________________________________________________________________________________

Variable name Comments about variable name

price

costoffirstitem

Ic

firstName

FYI: + concatenates two strings. The strings can be string literals or a variable containing string literals.


10

9. State what is displayed on the screen when the following program is executed:

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

Application Questions: Use the Python Interpreter to input your code and check your work

1. State a good variable name for an employees ID number. ________________________________

2. Write a line of Python code that prompts the user for the name of their favorite ice cream and stores it

in a valid variable name. __________________________________________________________

3. Crazy Sentence Program. Create a program that prompts the user for the name of an animal, a color,

the name of a vehicle, and the name of a city. Then print a sentence that contains the user input in the

following order. Include the additional words in the sample output as part of your output. Example:

Assume the user enters the words: tiger, green, motorcycle, and Wildwood. The output would be:

The green tiger drove the motorcycle to Wildwood. _________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________


Python Activity 3 Part A: Arithmetic Operations and Assignment Statements

11

Name: _______________________________________ Partners: ________________________________ Python Activity 3 Part A: Arithmetic Operations and Assignment Statements

Get the program to compute that! How do I assignment values to variables?


Python Program Flowchart Program

Learning Objectives


Content:

Explain each Python arithmetic operator

Explain the meaning and use of an assignment statement

Review string literals and print statements

Explain the use of + and * with strings and numbers

Use the int() and float() functions to convert string input to numbers for computation

Incorporate numeric formatting into print statements

Recognize the four main operations of a computer within a simple Python program Process:

Create input statements in Python

Create Python code that performs mathematical and string operations

Create Python code that uses assignment statements

Create Python code that formats numeric output

Prior Knowledge

Understanding of Python print and input statements

Understanding of mathematical operations


Further Reading



12

1. Execute the print statements in the Python program. What is the output for each statement? _________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

2. Draw a line between each flowchart symbol and its corresponding line of Python code.

3. Explain the purpose of each arithmetic operation: a. + ________________________________________________________________________

b. - ________________________________________________________________________

c. * ________________________________________________________________________

d. ** ________________________________________________________________________

e. / _______________________________________________________________________

f. // _______________________________________________________________________

g. % _______________________________________________________________________

FYI: An assignment statement is a line of code that uses a = sign. The statement stores the result

of an operation performed on the right-hand side of the sign into the variable memory location

on the lef0hand side.

4. Enter and execute the following two lines of Python code: age = 15 print(Your age is, age)

a. What does the assignment statement: age = 15 do?

______________________________________________________________________________

______________________________________________________________________________

b. What happens if you replace the comma (,) in the print statement with a plus sign (+) and execute

the code again? Why does this happen?

______________________________________________________________________________

______________________________________________________________________________

5. What is stored in memory after each assignment statement is executed?

Assignment Statement Computer Memory

answer = 6 ** 2 + 3 * 4 // 2 Answer

final = answer % 4 Final


13

6. What happens if you try to use the + with strings instead of numbers? Test the following program:

a. The third line of code contains an assignment statement. What is stored in fullName

when the line is executed?

______________________________________________________________________________

b. How can you fix the output so that the words are separated?

______________________________________________________________________________

c. What happens when you execute the following code? Why?

______________________________________________________________________________

______________________________________________________________________________

7. Before entering the following code into the Python interpreter, try to figure out what you think

the statement should print.

Now execute it. What does it do? Is this what you thought it would do?

______________________________________________________________________________

______________________________________________________________________________

8. Lets take a look at a program that prompts the user for two numbers and subtracts them. Execute the following code.

a. What output do you expect? _____________________________________________

b. What is the actual output? _____________________________________________

c. Revise the program in the following manner:

Between lines 2 and 3 add the following lines of code: num1 = int(firstNumber) num2 = int(secondNumber)

FYI: The + concatenates the two strings stored in the variables into one string. The assignment statement stored the results in the variable fullName. + can only be used when both operators are strings.


14

Next, replace the statement: difference = firstNumber secondNumber

with the statement: difference = num1 num2

Execute the program again. What output did you get? ________________________

d. Explain the purpose of the function int().

______________________________________________________________________________

______________________________________________________________________________

e. Explain how the changes in the program produced the desired output.

______________________________________________________________________________

______________________________________________________________________________

Application Questions: Use the Python Interpreter to check your work

1. Write the line of Python code that calculates and prints the answer to the following arithmetic

expressions:

a. 8 to the 4th power ___________________________________________________

b. The sum of 5 and 6 multiplied by the quotient of 34 and 7 using floating point arithmetic

_______________________________________________________________________

2. Write an assignment statement that stores the remainder obtained from dividing 87 and 8 in the

variable leftover

______________________________________________________________________________

3. Assume: courseLabel = CMSC courseNumber = 190

Write a line of Python code that concatenates the label with the number and stores the result in

the variable courseName. Be sure that there is a space between the course label and the course

number when they are concatenated. _________________________________________________________________

4. Create a program the outputs the total cost of a lunch order. Users should be prompted to input

the number of hamburgers, fries, and drinks they want and the program should print the total cost

of the order. The hamburgers cost 2.00, fries cost 1.50, and drinks cost 1.00. Be creative and

professional in prompting the user for the information and in displaying the output.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Name: _______________________________________ Partners: ________________________________ Python Activity 3 Part B: Arithmetic Operations and Assignment Statements

Get the program to compute that!


1. So far you have not been concerned about formatting output on the screen. Now you will discover

how Python allows a programmer to precisely format output. Some of the differences are very subtle,

so take notice of the differences in outputs.

Start by entering and executing the following code.

a. What is the problem with the manner in which the output is displayed?

_____________________________________________________________________________

______________________________________________________________________________

b. Replace the last line of code with the following: print("Total cost of laptops: %.2f" % price)

Discuss the change in the output.

_____________________________________________________________________________

______________________________________________________________________________

c. Replace the last line of code with the following: print("Total cost of laptops: $%.2f" % price)

Discuss the change in the output.

______________________________________________________________________________

______________________________________________________________________________

Learning Objectives


Content:

Incorporate numeric formatting into print statements

Recognize the four main operations of a computer within a simple Python program Process:

Create Python code that uses assignment statements

Create Python code that formats numeric output

Prior Knowledge

Understanding of Python print and input statements

Understanding of mathematical operations


Further Reading


Python Activity 3 Part B: Arithmetic Operations and Assignment Statements

16

d. Experiment with the number .2 in the print statement by substituting the following numbers and explain the results.

.4 ________________________________________________________________________

.0 ________________________________________________________________________

.1 ________________________________________________________________________

.8 ________________________________________________________________________

e. Now try the following numbers in the same print statement. These numbers contain a

whole number and a decimal. Explain the output for each number.

2.5 _______________________________________________________________________

8.2 _______________________________________________________________________

3.1 _______________________________________________________________________

f. Explain what the formatting code: %n.nf % variable does in a print statement where

n.n represents a number.

_____________________________________________________________________________

______________________________________________________________________________

g. Revise the print statement by changing the f to d and the decimal number to a whole number. Explain the sample formatting statements:

print("Total cost of laptops: %2d" % price) print("Total cost of laptops: %10d" % price)

______________________________________________________________________________

______________________________________________________________________________

h. Explain how %nd % variable formats numeric data. n represents a whole number.

______________________________________________________________________________

______________________________________________________________________________

2. Use the following program to answer the questions below.

FYI: Computers perform four main operations on data:

Input data into a computer

Output data to a screen or file

Process data using arithmetic, logical, searching or sorting operations

Store data


17

a. Using the code and comments in the program listed above, explain how the four main

operations are implemented in the program.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

b. There is one new concept exemplified in this sample program. What is it? From the

corresponding output, determine what it does.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________


1. Write one line of Python code that will print the word Happy! one hundred times. ______________________________________________________________________________

2. Assume: itemCost = input(Enter cost of item: ) a. Write one line of code that calculates the cost of 15 items and stores the result in the

variable totalCost

________________________________________________________________________

b. Write one line of code that prints the total cost with a label, a dollar sign, and exactly two

decimal places. Sample output: Total cost: $22.50

________________________________________________________________________

3. Assume: height1 = 67850 height2 = 456

Use Python formatting to write two print statements that will produce the following output

exactly at it appears below:

______________________________________________________________________________

______________________________________________________________________________

4. You have already completed the following program in a previous activity. Format the output.

Create a program the outputs the total cost of a lunch order. Users should be prompted to input the

number of hamburgers, fries, and drinks they want and the program should print the total cost of the

order. The price of hamburgers is 2.00, fries is 1.50, and drinks is 1.00. Be creative and professional

in prompting the user for the information and in displaying the output.

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________


18


Name: _______________________________________ Partners: ________________________________ Python Activity 4: Predefined Functions

How can I use the built-in code that is already part of Python?

Model 1: Predefined functions in Python

print(), round(), abs(), pow(), int(), etc. are known as predefined functions. Information that a function

needs to do its work is sent to the function between the parentheses (). This information is known as an

argument. To use a function, call the function. input(Enter your name) is a call to the input function sending the string Enter your name as an argument Critical Thinking Questions:

10. Circle the predefined functions in the following program.

11. Draw a line between each statement in the Python program and its corresponding statement in the flowchart.

Learning Objectives


Content:

Explain the purpose of a predefined function

Explain the functions: abs(), pow(), int() round(), random

Explain the math library functions: floor() and ceil()

Explain the use of the import statement

Explain the purpose of a function argument Process:

Write code that uses predefined functions

Prior Knowledge

Python concepts from Activities 1-3


Further Reading


Python Activity 4: Predefined Functions

20

12. Enter and execute the Python program on the previous page. a. What is the output for each statement ?

print(abs(-4.67)) _________________________

print(pow(5,3)) _________________________

print(pow(49,.5)) _________________________

print(int(34.8)) _________________________

print(round(6.9)) _________________________

import random print(random.randint(1,100)) ___________________

b. What is the difference between the round() function and the int() function?

______________________________________________________________________________

______________________________________________________________________________

4. What is the output for each line of code? Verify your answers by executing the code and explain the

answer given by the interpreter.

a. abs(4.5) _________________________________________________

b. int(678) _________________________________________________

c. round(-5.6) _________________________________________________

d. import random random.randint(4,10) ___________________________________________

What is the purpose of import random? What happens if you omit that line of code? ______________________________________________________________________________

______________________________________________________________________________

5. Write a definition of a predefined function.

______________________________________________________________________________

______________________________________________________________________________

6. Circle the argument in the following predefined function: number = 45.78 answer = round(number)

7. How many arguments can a function have? _______________________________________

8. answer = pow(4,3). What is/are the argument(s) in this code? ______________________

9. If a function contains more than one argument, do you think the order of the arguments makes a

difference? Explain your answer.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________


21

10. Execute the following code: import math x = 4.7

y = 5.3

z = -4.8

a = -3.2

print(math.ceil(x))

print(math.ceil(y)) print(math.ceil(z))

print(math.ceil(a))

print(math.floor(x))

print(math.floor(y))

print(math.floor(z))

print(math.floor(a))

a. Explain what the ceil() function does.

________________________________________________________________________

________________________________________________________________________ b. Explain the purpose of the floor() function.

________________________________________________________________________

________________________________________________________________________

c. Why are the calls to the math() and ceil() functions preceded by math.? ________________________________________________________________________

________________________________________________________________________


1. Write a line of code that prints the integer portion of the number 21.45.

______________________________________________________________________________

2. Write code that prompts the user for a floating point number and prints the smallest integer that is

larger than the number the user entered.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

3. Write a line of code that prints a random number between one and 6.

______________________________________________________________________________

______________________________________________________________________________

4. Assume that a user enters any number and that the number is stored in the variable userNumber.

Write a line of code that converts the input to a float. Then write a line of code that prints the

positive value of the users input. ______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

5. Write a line of code that calculates the square root of 900 and stores the result in the variable

answer. ______________________________________________________________________________


22

Notes and Questions Make note of any questions you have about Activity 4 on this page

Name: _______________________________________ Partners: ________________________________ Python Activity 5: Boolean Expressions and Selection Statements

True or False and making choices

Model 1: Programming Structures

Sequence Structure Decision or Branching Structure

Looping Structure


1. Each of the flowchart symbols in the chart above represents lines or segments of code. After

examining the chart, write a description of:

a. sequence structure ________________________________________________________

________________________________________________________________________

b. decision or branching structure _____________________________________________

_______________________________________________________________________

c. looping structure ____________________________________________________

________________________________________________________________________

Learning Objectives


Content:

Explain the three types of programming structures

Explain how conditional operators and logical operators are used in programming

Use conditional operators with strings and numeric values

Implement the Python syntax of an if/else statement

Determine good test data for programs that include if/else statements Process:

Write code that includes if statements and if/else statements

Write correct Boolean expressions and compound expressions

Prior Knowledge



Further Reading


Python Activity 5: Boolean Expressions and Selection Statements

24

2. Which structure best describes the types of Python programs you have written so far? Do you

think this structure is the best structure to use for all programs? Why or why not?

______________________________________________________________________________

______________________________________________________________________________

3. Which structure allows the programmer to create code that decides what code is executed?

_____________________________________________________________________________

Model 2: Conditional Operators

Conditional operators, also known as relational operators, are used to compare the relationship

between two operands. Expressions that can only result in one of two answers are known as

Boolean expression.

4. Determine the meaning of each of the following conditional operators.

If you are not sure of the meaning of any symbol, create some example

expressions, type them into the Python interpreter (see figure to the

right) and examine the results.

a. < ___________ b. > ____________

c. = ____________

e. != ___________ f. == ____________

5. What is the result of each of the following expressions?

Assume x = 4, y = 5, z = 4

a. x > y ______________________________________

b. x < y ______________________________________

c. x == y ______________________________________

d. x != y ______________________________________

e. x >= z ______________________________________

f. x 2 * x ______________________________________

h. y * x z != 4 % 4 + 16 ______________________________________

i. pow(x,2) == abs(-16) ______________________________________

6. What is the result of the following expressions?

Assume word1 = hello, word2 = good-bye

a. word1 == word2 ______________________________________

b. word1 != word2 ______________________________________

c. word1 < word2 ______________________________________

d. word1 >= word2 ______________________________________


25

7. Explain how the conditional operators are used when the operands are strings.

______________________________________________________________________________

______________________________________________________________________________

8. There are only two possible answers to the expressions in questions 5 and 6. What are they?

_______________________________________________________________________________

9. What is the Python code equivalent of the diamond flowchart symbol in the program above?

________________________________________________________________________

10. Enter and execute the following code. Use various values for the original cost and the sale price.

Explain what the following lines of code do. Each line appears in the program above.

a. originalPrice = int(originalPriceString)

________________________________________________________________________

b. percentOff =(originalPrice - salePrice)/originalPrice * 100

________________________________________________________________________

c. print("Sale price: $%.2f" %salePrice)

________________________________________________________________________

d. print("Percent off: %2d" % percentOff + "%")

________________________________________________________________________

e. if percentOff >= 50: print("You got a great sale!")

________________________________________________________________________

Model 3: IF/ELSE Statement

Flow chart Python Program


26

11. Revise the program in #10. If the percent off is 50% or more print Congratulations! in addition to what is already printed. Use a second print statement to do this. Write the code for this part

of the program.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

12. Revise the program in #12 so that it prints Done! when the program is complete no matter what the percent off is. How does the placement of this line of code differ from the placement of

the code created for #12?

______________________________________________________________________________

______________________________________________________________________________

Python Program

Flowchart

13. Compare the flowchart above with the corresponding Python Program. Carefully compare if/else

statement in the two programs. Enter and execute the Python program above.

a. Test the program at least three times. List the three test data you used and the

corresponding output. Explain why they were the best data to use as a test for the

program.

___________________ __________________ ___________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________


27

b. Now you want to add another print statement to the Python program above so that it

printed Thats really hot! when the water is 212 degrees or hotter. Rewrite the code below with this statement included.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

FYI: We can use logical operators to determine logic between conditions (relational expressions).

14. Sometimes you want to test more than one condition to determine which code segment should be

executed. You can use the following logical operators to create compound conditions. Examine

each operator and a sample of its use. Provide an explanation of how each operator works.

Operator Example Explanation

and (age >= 17) and (hasLicense = = true)

or (cost < 20.00) or (shipping = = 0.00)

not not (credits> 120)

15. Assume the value of the variable numBooks is 40. State the values of each of the Boolean

expression.

Expression Value

(numBooks > 5) and (numBooks < 100)

(numBooks < 5) or (numBooks > 100)

not(numBooks * 10 == 100)

16. Suppose you want to determine if a student is ready to graduate. The 3 criteria for graduation are

that the student has earned at least 120 credits, their major GPA is at least 2.0 and their general

GPA is also at least 2.0.

Missing Boolean expression


28

Which Boolean expression would be the correct test for Python code?

a. numCredits >= 120 or majorGPA >= 2.0 or overallGPA >= 2.0

b. numCredits > 120 and majorGPA > 2.0 or overallGPA > 2.0

c. numCredits > 119 and majorGPA >= 2.0 and overallGPA >= 2.0

d. numCredits >= 120 and majorGPA >= 2.0 and overallGPA >= 2.0

17. Enter and execute the program in #16. Include your choice for the correct Boolean expression.

Create several data sets to test all possibilities for the Boolean expression. List the data you used

to test all possibilities for the expression.

Data Set numCredits majorGPA overallGPA Expression Result (True or False)

1

2

3

4

5

6

7

8

9

10


1. Write a Boolean expression that tests if the value stored in the variable num1 is equal to the value

stored in the variable num2.

______________________________________________________________________________

2. Write a Boolean expression that tests if the value stored in the variable time is less than the value

stored in the variable maxTime or if the value stored in the variable cost is less than the value

stored in the variable maxCost

______________________________________________________________________________

3. Write the code for an if statement that adds 5 to the variable num1 if the value stored in the

variable testA equals 25. Otherwise subtract 5 from num1.

______________________________________________________________________________

4. Write the code for an if statement that prints a random number between one and 6 if the value

stored in the variable isValid equals the Boolean value true.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________


29

5. Write a Python program that prompts the user for the cost of two items to be purchased. Then

prompt the user for their payment. If they enter an amount that is less than the total cost of the

two items, print a message that tells them how much they still owe. Otherwise, print a message

that thanks them for their payment and tells them how much change they will receive.

Thoroughly test your code for all possible input.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

6. Write a Python program that prompts the user for a word. If the word comes between the words

apple and pear alphabetically, print a message that tells the user that the word is valid, otherwise,

tell the user the word is out or range.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

7. Write a Python program that prompts the user for a multiple of 5 between 1 and 100. Print a

message telling the user whether the number they entered is valid.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________


30


Name: _______________________________________ Partners: ________________________________ Python Activity 6: Functions

Modularizing your code


Python Program

Flowchart

Learning Objectives


Content:

Explain the meaning and purpose of a function

Recognize a function definition, function header, and function call in a program

Combine the use of functions with if/else statements

Explain programs that use the same function multiple times

Use good test data for programs that include functions Process:

Write code that includes function definitions and function calls

Write programs that incorporate functions and if/else statements

Prior Knowledge



Further Reading


Python Activity 6: Functions

32

FYI: A function is a segment of code that performs a single task.

1. Closely examine the flowchart and Python program above.

a. Draw arrows between each flowchart symbol and the equivalent Python code.

FYI: A function definition is the segment of code that tells the program what to do when the

function is executed. The first line of a function definition is known as the function

header

b. What Python keyword is used to indicate that a code segment is a function definition?

________________________________________________________________________

c. What is the function header in the Python code above?

________________________________________________________________________

d. The name of the function is in the function header. What is the name of the function?

________________________________________________________________________

e. Examine the Python function. Explain the syntax required for a function: indentation,

etc.

________________________________________________________________________

________________________________________________________________________

f. Enter and execute the Python program. What is the output?

________________________________________________________________________

g. What line of code would you add to the program to print the last two lines twice? Where

would you add the code?

________________________________________________________________________

________________________________________________________________________

2. Examine the following program

a. Label the function definition and the function call.

b. The function call and the function definition each include a variable within the

parentheses. The variable in this role is known as an argument. What is the argument in

the function definition? What is its purpose?

________________________________________________________________________

________________________________________________________________________


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c. In this example the argument in the function definition and the argument in the function

call have the same name. Is this required? _______________________________

d. Enter and execute the program. Verify your answer to question c by changing the variable name in the main program from radius to number. Do not change the variable

name in the function definition. Does the program still work? __________________

e. Write a line of code that calls the calculateArea function and sends the value 6 as the argument. Add the line of code to the main program and execute it to be sure it works

properly. _______________________________________________________________

f. Add a second function to the program that calculates and prints the diameter of a circle,

given the radius as an argument (parameter). Place the function definition above the main

part of the program. Write the function below.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

g. Add another line of code to the main part of the program that calls the function that was

created in part f. Send the radius entered by the user as the argument to the function. ________________________________________________________________________

3. What is the purpose of a function? Why do programmers use them?

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

4. Carefully examine the following program.

a. What is the first line of code executed by the Python interpreter?

________________________________________________________________________


34

b. Enter and execute the program. Use the following test data and indicate what the output

is for each set of data.

Data Set Operand 1 Operand 2 Operator Result

1 2 6 +

2 3 8 -

3 34 23 +

4 4 5 /

c. What problems did you notice when you entered Data Sets 3 and 4?

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

d. Add code to the program that would warn the user about the problems that could occur

when data similar to that in Data Sets 3 and 4 are entered. See sample output below. List

the lines of code below the sample output.

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________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

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35

FYI: So far, the functions you have printed any results within the function. They did not send

back any information to the original calling code. Functions that do not send back

information to where they are called are known as void functions. Functions often send

back or return the result and are known as value returning functions.

5. Enter and execute the code below. Carefully examine the code.

a. What is the new keyword used in the function definition? What do you think the

keyword tells the program to do?

________________________________________________________________________

________________________________________________________________________

b. Write the line of code from the program that includes the function call to getSmaller.

________________________________________________________________________

c. In a void function, the function call is on a line by itself. Why is this function call

placed on the right-hand-side of an assignment statement?

________________________________________________________________________

________________________________________________________________________

d. What are the arguments used for the function call? _______________________________

6. Examine the following Python program.

a. What does the program do?

________________________________________________________________________

b. Circle the function call. What is different about the placement of the function call?

________________________________________________________________________


36

c. Is the function a void function or a value returning function? ____________________

d. Why is the import statement needed in this program?

_______________________________________________________________________

7. The following Python program performs the same operations and produces the same output as the

previous program. Describe the major differences between the two programs. Edit the previous

program so that it looks like this one and execute it.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________


1. Write a function that draws a frog. Call the function to be sure it works. Sample frog:

______________________________________________________________________________

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2. Expand the program in #1 to produce the following output.

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

3. Write a Python program that prompts the user for three words and prints the word that comes last

alphabetically. Use a function to create the program.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

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38


Name: _______________________________________ Partners: ________________________________ Python Activity 7: Nested IF/ELSE Statements

Decisions, decisions decisions within decisions!


1. Closely examine the flowchart and Python program above.

Learning Objectives


Content:

Explain the purpose of a nested if-else statement

Explain how to use Python if-elif structure

Explain how to test code using Python if-elif structure Process:

Write code that includes if-elif statements

Write code that uses if-elif statements and functions

Prior Knowledge



Further Reading


Python Program

Flowchart

Python Activity 7: Nested IF/ELSE Statements

40


b. In the Python code, circle the if/else statement that is nested within another if/else statement.

c. Enter and test the code. List five numbers that you would use to test this program. Indicate why you chose the numbers.

Number Why chosen

2. Enter and execute the following Python program using the same data as you used for #1c.

a. How does the output for this program compare with the output for the previous program? ___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

b. What new keyword is used in this program? _______________________________________

c. Notice the syntax of this program compared to the previous program. Which program contains simpler indentation? _____________________________________________

FYI: elif is the Python keyword that represents else if and allows you to test for one of several options. As

soon as one of the tests is true, the rest are ignored.

d. You can use elif as many times as you need to. Suppose you wanted to add the comment Good! for grades that are between 80 and 89. Where would you add it? Write the code for this additional choice.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

e. Does the placement of an additional elif clause matter? ______________________________

f. When is the code associated with the else statement executed? ___________________________________________________________________________


41

g. Describe how an if/elif/else statement works. ___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

h. Change the program in #2 so that it prints the following messages. Write the code below.

Greater than 90 Very Good!

Between 80 and 89 Good!

Between 70 and 79 Satisfactory

Between 60 and 69 Fair

Less than 60 Poor

___________________________________________________________________________

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___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

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i. Make a final change to the program so that it prints an error message if the grade entered

is greater than 100 or less than 0.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

3. Is the use of the else statement mandatory when creating an if/elif statement? Explain your answer.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________


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1. Write an if/elif statement that assigns a value to the variable bonus depending on the amount of sales. Assume the amount of the sales is stored in a variable called sales.

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

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2. Carefully examine and then complete the following Python program. The program prompts the user to enter a number between 1 and 5 and also generates a random number between 1 and 5. The

program prints the number the user enters and prints the random number. The program then

compares the two numbers. If the numbers are the same, it prints the message You picked the same number as the computer!. If the number the user entered is higher than the random number, the program should print Your number is higher than the computers number. Otherwise, it should print: Your number is smaller than the computers number.

Explain what the if/else statement does in the Main Program.

Sales Bonus

>= 100,000 10,000

>= 75,000 5,000

>= 50,000 2,500

>= 25,000 1,000


43

.


44


Name: _______________________________________ Partners: ________________________________ Python Activity 8: Looping Structures WHILE Loops

Repeating code

Critical Thinking Questions

1. Closely examine the flowchart and Python program below.

FYI: A looping structure allows a block of code to be repeated one or more times. A while loop is

one of the two looping structures available in Python.

Python Program

Flowchart


b. In the Python code, circle all the code associated with the WHILE loop.

Learning Objectives


Content:

Explain the three parts of a loop

Explain the syntax of a while loop

Explain sentinel-controlled and counter controlled loops

Explain short-cut operators Process:

Write code that includes sentinel-controlled and counter controlled loops

Write code that uses short-cut operators

Prior Knowledge



Further Reading


Python Activity 8: Looping Structures WHILE Loops

46

c. Enter and test the code. What does the line of code: x=x+1 do?

___________________________________________________________________________

d. How does the Python interpreter know what lines of code belong to the loop body?

___________________________________________________________________________

e. Every loop structure requires three actions. Identify the line of code in the Python

program that corresponds to each of the three actions.

Initialize a variable used in the test condition:

________________________________________________________________________

Include a test condition that causes the loop to end when the condition is false:

________________________________________________________________________

Within the loop body, update the variable used in the test condition:

________________________________________________________________________

2. Enter and execute the following code.

a. Beside each line of code below explain what the code does.

b. Explain the difference between the two print statements.

________________________________________________________________________

________________________________________________________________________

3. The following code should print the numbers from 1 to 10, but it does not print anything.

Correct the problem.

number = 12 while number


47

b. What caused the output to be what it was?

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

c. Does the program end? Why or why not? ________________________________

_______________________________________________________________________

6. Enter and execute the following code: number = 1

while number


48

f. How many times does the loop execute? ______________________________________

FYI: A looping structure for which you know the number of times it will execute is known as a

count-controlled loop.

8. Sometimes a programmer does not know how many times data is to be entered. For example,

suppose you want to create a program that adds an unspecified amount of positive numbers

entered by the user. The program stops adding numbers when the user enters a zero or a negative

number. Then the program prints the total. Before creating this program, review the three actions

required for all loops:

a. Initialize a variable that will be used in the test condition: What will be tested to

determine if the loop is executed or not? Write a line of code that initializes a variable to

be used in the test condition of the loop for this program. The variable should contain a

value entered by the user.

________________________________________________________________________

b. Include a test condition that causes the loop to end when the condition is false: What is

the test condition for the while loop used in this program?

________________________________________________________________________

c. Within the loop body, update the variable used in the test condition: Write the code for

the loop body. Include the code to update the variable in the test condition.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

d. Is this a count-controlled loop? Why or why not?

________________________________________________________________________

e. Complete the program. Enter and execute the code. Does it work properly? __________

FYI: Short-cut operators provide a concise way of creating assignment statements when the

variable on the left-hand side of the assignment statement is also on the right-hand side. The

addition short-cut operator (+=) is usually used for incrementing a variable.

9. Enter and execute the following code: number = 1 number += 3

print(number)

a. What does the += shortcut operator do? ________________________________________________________________________

b. The code: x += 5 is equivalent to which of the following lines of code?

x = 5

x = y + 5

x = x + 5

y = x + 5


49

c. Replace the operator += with the following shortcut operators and execute the code. Explain what each operator does.

-= _________________________________________________________

*= _________________________________________________________

10. Enter and execute the following code: bonus = 25 salary += bonus print(Total salary:, salary)

a. What is the output of the preceding code? Is it what you expected?

________________________________________________________________________

b. Edit the code so that it produces valid output.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

c. As a result of correcting this code segment, what is needed in order for the shortcut

operators to work properly?

_______________________________________________________________________

d. Is the following line of code valid: 23 += total? Why or why not?

________________________________________________________________________

11. The following code should print the numbers beginning at 100 and ending with 0. However it is

missing a line of code. Add the missing code, using the shortcut operator. Indicate where the

code belongs. countdown = 100 while countdown > 0: print(countdown)

print(Done!)

________________________________________________________________________

12. Enter and execute the following code: doAgain = "y"

while doAgain == "y":

word = input("Enter a word:")

print("First letter of " + word + " is " + word[0])

doAgain = input("Type y to enter another word and anything

else to quit.")

print("Done!")

a. What does the program do?

________________________________________________________________________

b. What is the name of the variable used to store the users input? ____________________

c. In the print statement, what does word[0]represent? ___________________________


50

d. If you changed 0 to 1 in word[0]in the print statement above, what is printed?

________________________________________________________________________

e. When does the program end? _____________________________________________

g. Why is the loop in this program is an example of a sentinel control loop?

________________________________________________________________________

h. Examine the print statement in this program: print("First letter of " + word + " is " + word[0])

What is the purpose of the + as part of the argument in the print statement? What happens if you replace the + with a ,? ________________________________________________________________________

________________________________________________________________________

13. Examine the code below. name = Simone

cost = 3.56

numApples = 89

What type of data is stored in each variable: (integer, floating point, or string)

name __________________________

cost __________________________

numApples __________________________

FYI: A variable that can store only the values True and False is called a Boolean variable.

14. Given the assignment statement: foundCost = False

What value is stored in the variable foundCost? ________________________________

What type of data is stored in foundCost? ________________________________

15. Enter and execute the following code:

a. What type of variable is doAgain? _______________________________________

FYI: A sentinel-controlled while loop is a loop that repeats the loop body until the user enters a pre-

specified value.


51

b. What does the program do?

________________________________________________________________________

________________________________________________________________________

c. What does the following line of code do? maxNum1 = max(num1, num2, num3, num4)

________________________________________________________________________

d. Experiment with the arguments in the max() function in the program to determine if the

function must have four arguments. Demonstrate your answer.

________________________________________________________________________

________________________________________________________________________

e. What does the following code in the program do? if another != 'y':

doAgain = False

________________________________________________________________________


1. Write a code segment that prompts the user for an even number. As long as the number is

not even, the user should be given a message and prompted again for an even number.

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

2. Write code segment that prompts the user for a letter from a-z. As long as the character is not between a-z, the user should be given a message and prompted again for a letter between a-z. ______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

3. Complete the following program:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________


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53

Name: _______________________________________ Partners: ________________________________ Python Activity 9: Looping Structures: FOR Loops

Another form of loops


4. Enter and execute the following two Python programs.

WHILE LOOP -- Python Program

FOR LOOP Python Program

a. What is the output for each program?

___________________________________________________________________________

b. Both programs produce the same output. Which code fragment is more concise?

___________________________________________________________________________

FYI: The Python predefined range() function is used to define a series of numbers and can be used in

a FOR loop to determine the number of times the loop is executed..

2. Enter and execute

python workbook olivieri

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