Accessing Tab Delimited Field in Perl One-Liner

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

Given such data (mydat.txt)

foo 1.02
bar 0
qux 2.33
tuq 0
[download]

The following is the typicall AWK ways to access field, by printing lines where the value of second column is 0 (zero).

$ awk '$2==0; {print}' mydat.txt
[download]

What's Perl one-liner way to do it?

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neversaint and everlastingly indebted.......

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Re: Accessing Tab Delimited Field in Perl One-Liner by jwkrahn (Abbot) on Jun 01, 2009 at 01:32 UTC
`perl -ane'$F[1] \|\| print'` [download]	[reply] [d/l]
Re^2: Accessing Tab Delimited Field in Perl One-Liner by aufflick (Deacon) on Jun 01, 2009 at 01:42 UTC
Dang, -a/-F was what I was forgetting. For anyone who, like me, constantly forgets the commandline arguments, `perldoc perlrun` is your friend.	[reply] [d/l]
Re^2: Accessing Tab Delimited Field in Perl One-Liner by Marshall (Canon) on Jun 01, 2009 at 19:39 UTC
Just another way if you forgot about -a (autosplit), slightly longer, but is runnable code within a script... `perl -ne "(split)[1] \|\| print" temp.txt #same thing... perl -ne "print if !((split)[1]);" temp.txt` [download] A Perl variable evaluates to false if either: undefined, numeric zero or "" (empty string). Update: also of note: default split operates on whitespace which is (\s\t\f\r\n). Above would work fine with combination of spaces and tabs between tokens.	[reply] [d/l]
Re: Accessing Tab Delimited Field in Perl One-Liner by aufflick (Deacon) on Jun 01, 2009 at 01:32 UTC
There is for sure going to be a shorter more golf-ish solution, but the obvious one is: `perl -ne '@cols = split /\t/; print if $cols[1] == 0' mydat.txt` [download] -n means iterate the next block of code over the supplied files one line at a time (where line means whatever is separated by the value of $/ which is the newline of your platform by default). The text line is presented in the variable $_ with a newline. -e means interpret the next commandline argument as a chunk of code. Many builtins, such as split, print and // regex matching, operate on $_ by default if no string/list argument is given.	[reply] [d/l]
Re: Accessing Tab Delimited Field in Perl One-Liner by citromatik (Curate) on Jun 01, 2009 at 06:57 UTC
BTW... your awk version is terribly verbose :-) `awk '$2==0' mydat.txt` citromatik	[reply] [d/l]