(jeffa) Re: Array to hash refs

Here is all i could come up with:

use strict;

my @a = ('a'..'f');
my $hash;
my $last = 1;

for (reverse @a) {
   $hash->{$_} = $last;
   $last = {$_ => $hash->{$_}};
}
delete $hash->{$a[$_]} for (1..@a);
[download]

Hehehe, i waited until Abigail-II posted first though. Now i am going to spend some time figuring out how that works ... need more coffee!

UPDATE: Ok, let's figure Abigail-II's code out ...

When dealing with loops, a good way to understand the code is to chart out what happens at each iteration -

Iteration 1:

@array = ('a','b','c');
atomic:

$hash = undef;
$hash->{a} = $val; # $val = 1
$val = $hash;

# is ('b','c') > 1 ? yes

Iteration 2:

@array = ('b','c');
atomic:

$hash = undef;
$hash->{b} = $val; # $val = {a => 1}
$val = $hash;

# is ('c') > 1 ? no

Last line: (note that $hash is currently undef)

$hash->{c} = $val; # $val = {b => {a => 1}}

The key to this code is the atomic triple assignment inside the while loop. Break that into 3 seperate assignments and the results are not the same. Abigail-II++ :)

UPDATE*2:
I think i like Anony's answer the best ... now that is using Perl to write Perl! /smack forehead

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

Comment on (jeffa) Re: Array to hash refs Download Code

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Re: (jeffa) Re: Array to hash refs by Abigail-II (Bishop) on Aug 14, 2002 at 09:18 UTC
You can break it into 4 separate assignments though.... Abigail	[reply]