On Mar 25, 2014, at 6:55 AM, shawn wilson <[email protected]> wrote:
> i want to sort an array for certain key words first and then alphabetically.
>
> my @foo = qw/foo bar baz first second third/;
>
> foreach my $i (sort {$a cmp $b} @foo) {
> print "$i\n";
> }
>
> How do I make 'first', 'second', and 'third' come before the rest?
> (I'm actually dealing with a hash)
You need to write a sort comparison function that will return:
-1 if $a is a primary key and $b is not
+1 if $b is a primary key and $a is not
a normal comparison value if either both or neither are a primary key
Here is one way:
#!/usr/bin/perl
use strict;
use warnings;
my @keys = qw( foo bar baz first second third );
my %primary = ( first => 1, second => 1, third => 1);
my @sorted;
@sorted = sort {
if( ! ($primary{$a} xor $primary{$b}) ) {
return $a cmp $b;
}elsif( $primary{$a} ) {
return -1;
}else{
return +1;
} } @keys;
print "Sorted: ", join(', ',@sorted), "\n”;
You could also prepend ‘1’ to your primary keys and ‘2’ to the other keys, do
the sort, then strip the digits.
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