http://www.perlmonks.org?node_id=584614


in reply to Re^2: Sorting files you Have read
in thread Sorting files you Have read

Ok, lets give that "simple effective" sample code some data:

use strict; use warnings; my @contents = sort <DATA>; print @contents; __DATA__ At the moment, due to the small file size, sort time is unimportant. At some point, when I get to that stage, the sorted data will be reuse +d. I tried your code, and it seems quite simple, hence, efective. BUT, It runs with no errors, but nothing prints.

Prints:

At some point, when I get to that stage, the sorted data will be reuse +d. At the moment, due to the small file size, sort time is unimportant. BUT, It runs with no errors, but nothing prints. I tried your code, and it seems quite simple, hence, efective.

which is sorted on the whole line. It works, but ain't what you want. So lets add in some brain hurty code to sort by the "second column": :)

use strict; use warnings; my @contents = map { $_->[0] } sort { $a->[1] cmp $b->[1] } map { [$_, extractColumn (1, $_)] } <DATA>; print @contents; sub extractColumn { my ($columnIndex, $line) = @_; my ($key) = $line =~ /(?:[^,]*,){$columnIndex}([^,]*)/; return $key; } __DATA__ At the moment, due to the small file size, sort time is unimportant. At some point, when I get to that stage, the sorted data will be reuse +d. I tried your code, and it seems quite simple, hence, efective. BUT, It runs with no errors, but nothing prints.

Prints:

BUT, It runs with no errors, but nothing prints. I tried your code, and it seems quite simple, hence, efective. At the moment, due to the small file size, sort time is unimportant. At some point, when I get to that stage, the sorted data will be reuse +d.

However if you are dealing with csv (comma separated variable) data then you really want to be using a module such as Text::CSV to read the file. You may like to check out a few nodes that have asked the "sort CSV" question before (Super Search SoPW remember): Sorting a CSV file and sorting CSV files may help too.


DWIM is Perl's answer to Gödel