Re^2: better way to convert a string into an array and an hash

You are using s///ge only for the side effects of the code in the substitution part. Why do you need a substitution then? You could just as well say

use warnings; use strict;
my $string = "1:1,2:1,3:2,500:2,505:1"; 
my (@array, %hash); 
while ($string =~ /(\d+):(\d+)(?:,|$)/g) 
        { $hash{$1}=$2;push(@array, $1) }; 
use Data::Dumper; 
print Dumper(\@array, \%hash);
[download]

Comment on Re^2: better way to convert a string into an array and an hash Select or Download Code

Replies are listed 'Best First'.
Re^3: better way to convert a string into an array and an hash by fergal (Chaplain) on Oct 05, 2004 at 20:50 UTC
Simply because it gives you a free loop. I first saw this idiom about 10 years ago for decoding a cgi params into a hash. Something like `$p =~ s/(.?)=(.?)(&\|$)/$v=$2;$v=~s/%(..)/chr(hex($1))/ge;$p{$1}=$v/g +e` [download] a substitution within a substiution! I also thought it might be quicker but after a quick benchmark it seems not. I suppose I could have used `[/(\d+):(\d+)(?:,\|$)(?{$hash{$1}=$2;push(@array, $1);1})/g];` [download] for a free loop without destroying the string but isn't much faster.	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^3: better way to convert a string into an array and an hash
by fergal (Chaplain) on Oct 05, 2004 at 20:50 UTC

Simply because it gives you a free loop. I first saw this idiom about 10 years ago for decoding a cgi params into a hash. Something like

$p =~ s/(.*?)=(.*?)(&|$)/$v=$2;$v=~s/%(..)/chr(hex($1))/ge;$p{$1}=$v/g
+e
[download]

I also thought it might be quicker but after a quick benchmark it seems not.

I suppose I could have used

[/(\d+):(\d+)(?:,|$)(?{$hash{$1}=$2;push(@array, $1);1})/g];
[download]

[reply]
[d/l]
[select]