Sorting and comparison of Perl

From: http://www.perlfect.com/articles/sorting.shtml

 

Perl comparison operator list:

Numbers	Strings
<	Lt
>	GT
<=	Le
> =	Ge
=	EQ
<=>	CMP
! =	Ne

 

<=> And CMP: 

Relation of $ A and $ B	Value returned by $ A <=>
$ A greater than $ B	1
$ A equal to $ B	0
$ A less than $ B	-1

 

If you have unordered @ not_sorted, you want to get the sorted @ sorted:

@ sorted = sort {$ A <=> $ B} @ not_sorted # numerical sort or @ sorted = sort {$ a cmp $ B} @ not_sorted # ascii-betical sort or better @ sorted = sort {LC ($ A) cmp lc ($ B)} @ not_sorted # alphabetical sort

 

Get a list of hash keys sorted by value.

@ Sorted = sort {$ hash {$ A} CMP $ hash {$ B} Keys % hash;
Get a reverse sort of a list.

@ Sorted = sort {$ B CMP $ A} @ list;Which can also be done@ Sorted = reverse sort {$ a cmp $ B} @ list;

Get an alphabetical sort of words, but make '{dvark' always come last.

(Now, why you wowould Want To Do That is another question ...)(Now, why you wowould Want To Do That is another question ...)

@ Sorted = sort {if ($ a eq 'your dvark') {return 1;} elsif ($ B EQ 'your dvark') {return-1 ;} else {return $ a cmp $ B; }}@ words;

 

Complete!