topic Re: Comparing columns in a file help in Operating System - HP-UX

Comparing columns in a file help

Michael Barron — Mon, 04 May 2009 15:20:14 GMT

I have a file that contains 2 columns.

file1:
10.994 14.514
13.506 16.587
16.156 15.597
14.008 13.609
12.617 14.532

I need to compare the 2 columns and determine that if column 2's value is greater than column 1's value by double or more I want to know about it. basically just print the row that meets that above standards. Any ideas?

Re: Comparing columns in a file help

Michael Mike Reaser — Mon, 04 May 2009 15:47:35 GMT

None of the data you show meets your criteria of "column 2's value is greater than column 1's value by double or more".

Or, are you wanting all lines where column 2 is simply greater than column 1?

Your data, and your description, do not go together, at all.

Now, presuming that your description is what you want, the following awk command should work for you:

awk '{a=$1*2;if(a>=$2){print $0}}' < input_file

This will display back to stdout all lines where the value in column 2 is twice or more the value in column 1.

Re: Comparing columns in a file help

Michael Barron — Mon, 04 May 2009 15:51:25 GMT

Mike,

Thanks, the file was just an example, there are hundreds and hundreds of lines in the file and happen to grab some that dont work. Thanks again for the idea. I'll test it out and see if its what I need, i appreciate your help

Re: Comparing columns in a file help

Michael Barron — Mon, 04 May 2009 16:05:18 GMT

Th awk statement works, but I get mixed results.
1.242 4.363 (Works here)
1.268 8.955 (Works here)
1.346 0.888 (Not here)
1.195 0.992 (Not here)

Thanks again for your help

Re: Comparing columns in a file help

Michael Mike Reaser — Mon, 04 May 2009 16:29:26 GMT

That's because the conditional I listed is backwards. The correct awk command should be

awk '{a=$1*2;if(a<=$2){print $0}}' < input_file

Whoops, and sorry. :-)

Re: Comparing columns in a file help

Michael Barron — Mon, 04 May 2009 16:33:25 GMT

Awesome, works perfect, thanks again!

Re: Comparing columns in a file help

Viktor Balogh — Tue, 05 May 2009 09:04:01 GMT

here is another solution with a while loop in ksh:

# while read col1 col2; do if [ $(echo $col1*2000 | bc ) -lt $(echo $col2*1000 | bc ) ];then echo $col1 $col2;fi;done < inputfile