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...