Chas. Owens wrote:
On Mon, Jun 15, 2009 at 11:28, Aimee Cardenas<aim...@sfbrgenetics.org> wrote:
I have a file with two important columns in it separated by spaces. I'll
call these col1 and col2. I need to sort the data by col2 and then print
col1 & col2 to a file. I know I CAN do it with perl, but which way is
faster for this kind of processing? Perl or Awk? I know with awk, I can
find a one-liner for the command line and I could probably do that with
perl, too (I'm just now refreshing myself on perl command line options), but
I just thought I'd get some experienced opinions on the best way to do it.
Thanks in advance. May your sky be filled with perly clouds! ;-)
Aimee
Sounds like a job for a Schwartzian Transform[1]:
lexical sort
perl -e 'print map { join(" ", @$_), "\n" } sort { $a->[0] cmp $b->[0]
} map { [split] } <>' filename
The OP said they want to sort "by col2" so that should be sort { $a->[1]
cmp $b->[1] }
numeric sort
perl -e 'print map { join(" ", @$_), "\n" } sort { $a->[0] <=> $b->[0]
} map { [split] } <>' filename
sort { $a->[1] <=> $b->[1] }
Or perhaps a GRT instead:
perl -le'print for map join( "", reverse /(\S+)(\s+)(\S+)/ ), sort map
join( "", reverse /(\S+)(\s+)(\S+)/ ), <>' filename
John
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annoyance to those of us who do. -- Isaac Asimov
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