Array Sort

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

Hello, I hate to waste your time with such a simple question, but I need to sort an array that consists of numeric elements.

The sort routine does the job, but only looks at the first digit of each element. This works for single numbers, but my array contains 2 or more digit numbers, This is the code I'm working with;

use strict;

@event_queue = ("18", "503", "103", "501", "53");

@event_queue = sort(@event_queue);
foreach $_ (@event_queue){
    print "$_\n";
}
[download]

This produces:

103
18
502
503
53
[download]

The sort should look like this:

18
53
103
502
503
[download]

Any suggestions?

Comment on Array Sort Select or Download Code

Replies are listed 'Best First'.
Re: Array Sort by davis (Vicar) on Sep 10, 2002 at 11:42 UTC
That's because sort does a lexical sort by default, and you want a numerical sort. Compare the "magic" sort variables $a and $b using the spaceship operator. `perldoc -f sort` Reveals the following: `# sort numerically ascending @articles = sort {$a <=> $b} @files; # sort numerically descending @articles = sort {$b <=> $a} @files;` [download] Cheers Update:Ahah!. Knew it was around here somewhere! Under Categorized Questions and Answers, in the sorting subsection (Although it might benefit from being in the array section as well), you'll find How do I sort a list of numbers? davis Is this going out live? No, Homer, very few cartoons are broadcast live - it's a terrible strain on the animator's wrist	[reply] [d/l]
Re: Array Sort by JaWi (Hermit) on Sep 10, 2002 at 11:44 UTC
That's because it handles each element of your array as string. You probably want this: `... @event_queue = sort { $a <=> $b } @event_queue; ...` [download] BTW: you don't need to explitly assign the $_ operator in the foreach loop. It is done automatically... Greets, -- JaWi "A chicken is an egg's way of producing more eggs."	[reply] [d/l]
Re: Re: Array Sort by The_Rev (Acolyte) on Sep 10, 2002 at 11:53 UTC
That worked! I always learn something when I post, like the absence of $_ in a foreach loop Thanks Again!	[reply]
Re: Array Sort by Anonymous Monk on Sep 10, 2002 at 16:45 UTC
Sorting positive integers using the Guttman Rosler Transform: `@event_queue = ("18", "503", "103", "501", "53"); @event_queue = map{(split)[1]} sort map{(length length).(length)." $_"} @event_queue;` [download]	[reply] [d/l]
Re2: Array Sort by blakem (Monsignor) on Sep 11, 2002 at 01:44 UTC
See Re:x3 The High Price of Golf, and A Surprise and the subthread its in, then decide if a GRT makes any sense in this case.... Also, the code above will fail if your integer happens to look like `"1.0"` instead of the canonical `1` -Blake	[reply] [d/l] [select]