CODEWITHSUNDEEP
arraysperlsorting
user2705120
user2705120

Reputation: 249

Sorting in Perl

I'm new to Perl and stuck with an array sorting problem.

For example if my input is

@lines =  qw/ S-1.1 A-1.4 V-1.3 /

output should be in the order

A-1.4, V-1.3, S-1.1.

The idea is sort out based on what comes after - in the string. I tried sort {$a <=> $b} @lines but it did not help.

Please advise some idea to get this done.

Upvotes: 2

Views: 187

Answers (2)

Nate
Nate

Reputation: 1921

use strict;  
use warnings;

my @lines = ("S-1.1", "A-1.4", "V-1.3"); 
@lines = sort { (split /-/, $b)[1] <=> (split /-/, $a)[1] } @lines; 
print join ', ', @lines;

output

A-1.4, V-1.3, S-1.1

Upvotes: 3

pts
pts

Reputation: 87421

my @lines = qw(S-1.1 A-1.4 V-1.3);
@lines = sort { substr($a, index($a, '-') + 1) <=>
                substr($b, index($b, '-') + 1) } @lines;
print "@lines\n";  #: S-1.1 V-1.3 A-1.4

If you want to have more than one dot in the strings, it becomes a bit more complicated:

sub pad($) {
  local $_ = $_[0];
  s/^[^-]*?-//;
  s/(\d+)/sprintf("%020d",$1)/ge;  
  $_
}
my @lines = qw(S-1.2.12 B-1.2.9 A-1.4 V-1.3);
@lines = sort { pad($a) cmp pad($b) } @lines;
print "@lines\n";  #: B-1.2.9 S-1.2.12 V-1.3 A-1.4

Upvotes: 1

Related Questions