printing line number

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi all. I have a file with two columns of data, x and y. If both are equal i need the line number that this occurs on.

file
1  2
2  2
3  1
[download]

i.e print line number 2 i guess i could use a counter and go through the file but any other suggestions? Thanks

Comment on printing line number Download Code

Replies are listed 'Best First'.
Re: printing line number by VSarkiss (Monsignor) on Sep 16, 2004 at 15:09 UTC
Look in perlvar for `$.`, the current input line number. Presuming it's on `STDIN` and the columns are separated by white space: `my @columns = split /\s+/; print $., "\n" if $column[0] == $column[1];` [download]	[reply] [d/l] [select]
Re^2: printing line number by Anonymous Monk on Sep 16, 2004 at 15:19 UTC
thanks for that, i guess therefore it is possible to use % with $. to print lines based on %	[reply]
Re: printing line number by sweetblood (Prior) on Sep 16, 2004 at 15:11 UTC
Sounds like homework so I'll just give you a hint: check out $. perldoc perlvar Sweetblood	[reply]
Re: printing line number by Random_Walk (Prior) on Sep 16, 2004 at 15:19 UTC
First will print line No if numericaly equal or string equal, second only for lines with equal numbers `perl -ne 'print $. if /^(.+)\s+\1$/' perl -ne 'print $. if /^(\d+)\s+\1$/'` [download] Cheers, R.	[reply] [d/l]
Re: printing line number by graff (Chancellor) on Sep 17, 2004 at 08:37 UTC
`perl -lane 'print $. if $F[0]==$F[1]' file` [download] Replace '==' with ' eq ' if you would prefer a string comparison rather than numeric (and use double quotes instead of single-quotes if you're using a DOS shell).	[reply] [d/l]