Awk - select from a list

simha77777 · #1 (**permalink**) 02-06-2008

Hi all,

I am trying to select some columns from a file, based on the list of values.
Would like to know how best I can achive this.

If coulmn 1 has a value of 57 then print the ist column (This works)

Code:

awk -F'  ' '{if ( $1 == 57 ) {print $1}}' file.txt

Now my requirement is that I have to check the column with multiple values. (If I have 2 use an OR operator as below)

Code:

awk -F'  ' '{if ( $1 == 57 || $1 == 58) {print $1}}' file.txt

I have 100 values which I need to check with the first column. Is there a way to do this, without writing in 100 conditions in the if statement?
(I could put the 100 values into a file if that makes things easier)

Please let me know if you need more information. Any help greatly appreciated.

Yogesh Sawant · #2 (**permalink**) 02-06-2008

how about putting a regex instead of those hundred comparisons?

simha77777 · #3 (**permalink**) 02-06-2008

Thank you for the response.

In my case, I don't have a definite pattern to use as a regexp, I would have to pass a list of numbers, which might not be in a sequence.
HTH

vgersh99 · #4 (**permalink**) 02-06-2008

assuming numberList is a file containing 'numbers' to be filtered - one number per line.
And 'myFile' is a file to check the numbers against.

nawk -f simha.awk numberList myFile

simha.awk:

Code:

NR==FNR { numList[$1]; next}
$1 in numList {print $1}

simha77777 · #5 (**permalink**) 02-06-2008

vgersh99,

Pardon my ignorance -
Just a little clarification needed here.
numList and numberList mismatch is a typo or it needs to be that way?

Also how do I check for a particular coulmn in the myFile (for example the 14th coulmn). The delimiter is tab in myFile.

Thanks for your time.

vgersh99 · #6 (**permalink**) 02-06-2008

Quote:

Originally Posted by simha77777

vgersh99,

Pardon my ignorance -
Just a little clarification needed here.
numList and numberList mismatch is a typo or it needs to be that way?

no, it's not a typo - it can be anything

Quote:

Originally Posted by simha77777

Also how do I check for a particular coulmn in the myFile (for example the 14th coulmn). The delimiter is tab in myFile.

Thanks for your time.

if it's the 14-th column in the myFile, then change this:

Code:

$1 in numList {print $1}

to this:

Code:

$14 in numList {print $14}

simha77777 · #7 (**permalink**) 02-06-2008

Not sure what I am doing wrong, but I am not getting any results when i run the command

Code:

nawk -f simha.awk numberList myFile

numberList is my single column file with the numbers which are used to compare.
myFile is my tab delimited file whose 14th colunm needs to be compared to the values in the numberList file.
simha.awk has the exact code you have specified (The one with 14)

Appreciate your help so far.

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