my $slice = {
    kind    => $kind,
    prop    => $prop,
    item    => [ 5..11 ],
};
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use strict;
use warnings;

my $kind = 'alph';
my $prop = 'single';

my $slice = {
    kind    => $kind,
    prop    => $prop,
    item    => [5..11]
};

my @item_2 = @{$slice -> {item}};
my $num = scalar @item_2;
map {print "num is $num the $_\n";} @item_2;
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prints:

num is 7 the 5
num is 7 the 6
num is 7 the 7
num is 7 the 8
num is 7 the 9
num is 7 the 10
num is 7 the 11
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Is this what you are after?

As others have mentioned, psuedohashes were an experiment that didn't pan out, and are been deprecated in perl 5.8 and gone in perl 5.10.

I thought I'd add to what others have shown you here by suggesting that you try out Data::Dumper. It is very helpful when trying to understand datastructures. Try this code:

use Data::Dumper;
my $slice = {
    kind => 'alph',
    prop => 'single',
    item => 5..11,
}
print Dumper $slice;
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While you are looking at perldoc.perl.org, check out perldsc--the data structures cookbook. There's good stuff in there on setting up nested structures.

I also noticed that you use map to iterate over your @item_2 array, but don't use the return value--in other words, you are using map in a void context. Some people think this is a bad idea. Others don't have a problem with it. I don't really care, one way or the other. Anyhow, in case you decide you don't like void map, I'll show a couple of ways to do the same thing without raising that stylistic bugaboo:

# print takes a list of arguments
# here map generates a list of args for one call to print.
print map {
    "num is $num the $_\n"
} @item_2;

# simply replaced map with foreach used as a statement modifier.
print "num is $num the $_\n" 
    foreach @item_2;
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Thanks for all the replies which are very instructive! (1) Thanks for leting me know that using following statement is referred to another hash which is not what I expected.

my $slice = {
    kind    => $kind,
    prop    => $prop,
    item    => 5..11
};
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(2) Thanks for pointing out the dereference method like:

my @items = @{$slice -> {item}};
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I don't really understand why I need use @{} here to dereference, can somebody explain it for more details? I am just a Perl newbie :)
(3) Thanks for present a good program for data structure viewer -- Data::Dumper. I guessed I heard of it sometime ago, now I know how to use it. It's a good toolkit for debugging too.
(4) Thanks for criticizing my bad coding style (using map in a void context). I am digging into the link to find out why I should avoid to use this style... :)

(4) Thanks for criticizing my bad coding style (using map in a void context). I am digging into the link to find out why I should avoid to use this style... :)

Don't be too hard on yourself for this one. Void map/grep have been argued over for years in the perl community. Some don't see a problem with it, others do. Definitely look into the issue and decide for yourself what is right.

I'm personally neutral on void map. I use foreach in most cases where a void map could be used, because I think it more clearly expresses the intent of the code. However, I would have no problem using a void map if I thought it made things more readable.

You might like to check out this nice article on void map


TGI says moo

I don't really understand why I need use @{} here to dereference, can somebody explain it for more details?

By using the square brackets, you have created a reference to an array. Since you want to access the elements of the array reference, you first need to de-reference the array. One way to do so is to use the @{} syntax. Here are some good resources on the topic:
• References quick reference
• perlreftut
• perldsc
• perllol

my $slice = {
    kind    => $kind,
    prop    => $prop,
    item    => 5, 6, 7, 8, 9, 10, 11
};
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my $slice = {
    kind    => $kind,
    prop    => $prop,
    item    => 5,
    6       => 7,
    8       => 9,
    10      => 11
};
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I can't see where you are using the pseudohash feature. This is just as well, because the feature is deprecated.

If you don't know what a pseudohash is, don't bother to find out. Just say hash.

Its beyond deprecated :) its gone (Pseudo-hashes have been removed)