Re: Ordering keys in a hash

[Alexander von Below]

Well, I am not sure if this helps you, maybe you knew that all along:

A normal, ascending sort would be

my @keys = sort { $a <=> $b } keys(%gene_pool);

The criterion function, should return:

an integer less than 0: if $a is to be sorted before the $b
0: if $a and $b are equal
an integer greater than 0: if $a is to be sorted after $b
The "spaceship operator" does just that. To reverse order, just use $b 
<=> $a for example

Alex

Am Dienstag, 05.08.03 um 17:12 Uhr schrieb Adam Witney:

Hi,

I have a hash with keys of the format

sar0011_4
sar0203_3
sar0050_5
sar2001_1
sar0002_9
And I would like to generate a list ordered by the \d\d\d\d bit in the
middle. I have this from the perl cookbook
my @keys = sort {criterion()} keys(%gene_pool);

but I don't really know how to approach the criterion() function

Anybody have any suggestions?

Thanks for any help

Adam

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