vlookup presentation
TRANSCRIPT
How I filter data with MS Excel’s VLOOKUP() function
Anneke M. Batenburg
RationaleThis is what my raw measurement data usually look like, after I export them from Isodat.This file includes six peaks of each chromatogram, whereas I’m only interested in one peak (sample peak) per chromatogram.Selecting the data I want by hand is TEDIOUS.
Enter: VLOOKUP()
VLOOKUP searches for a value in the first column of a table array and returns a value in the same row from another column in the table array.
Syntax:VLOOKUP(value_to_look_for, array_to_look_in, column_number_to_return_value_from, boolean_that_should_always_be_FALSE_in_my_cases)
One complication: my data should have a first column with lookup labels (value_to_look_for)
Create a lookup label
I create a first column with a formula that detects • if the peak is a sample
peak (based on retention time),
• and if yes, gives it a sequential number.
Ax=IF(AND(260 < Kx , Kx < 625), MAX(A$2:Ax)+1,"")
Create a sheet with selected data
Now I create another sheet where I use VLOOKUP() to look up the data I want automatically.Like the filename of the chromatograms that yielded a sample peak.
Ax=VLOOKUP(ROW()-1, ’SheetName'!A$2:Z$207, 2, FALSE)
And I can look up more data, as desired.
Many more variations are possible, like selecting only the measurements that have “NAT334” or “BLANK” in the filename, or selecting only measurements from a particular measurement day...