perl sort <=> and cmp

Perl has two operators <=> and cmp,

which are very useful when wishing to sort arrays. $a <=> $b returns -1 if $a is numerically lesser than $b,1 if it's greater,and zero if they are equal.

cmp does the same for string comparison. For instance the prevIoUs example Could be re-written as:

 [liuguiyou@localhost perl]$ cat sort.pl
 #!/usr/bin/perl

 use strict;
 use warnings;

 my @array = (100,5,8,92,-7,34,29,58,10,24);

 my @sorted_array = sort { $a <=> $b } @array;

 print join("<",@sorted_array),"\n";

 [liuguiyou@localhost perl]$ ./sort.pl
 -7<5<8<8<10<24<29<34<58<92<100
 
   

Much more civil,isn't it? The following example,sorts an array of strings in reverse:

 [liuguiyou@localhost perl]$ cat sort_chara.pl #!/usr/bin/perl  use strict; use warnings;  my @input = (     "Hello World!",    "You is all I need.",    "To be or not to be",    "There's more than one way to do it.",    "Absolutely Fabulous",    "Ci vis pacem,para belum",    "Give me liberty or give me death.",    "Linux - Because software problems should not cost money",);  # Do a case-insensitive sort my @sorted = sort { lc($a) cmp lc($b); } @input;  print join("\n",@sorted),"\n";   [liuguiyou@localhost perl]$ ./sort_chara.pl Absolutely Fabulous Ci vis pacem,para belum Give me liberty or give me death. Hello World! Linux - Because software problems should not cost money There's more than one way to do it. To be or not to be You is all I need.