array splice vs hash splice

kiat has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

Just out of curiosity...

An array is prefixed with @ and so when you want to do an array splice, you also use @ to get to the elements:

my @array = qw(one two three four five);

print "@array[2,3]\n";
# prints three four
[download]

A hash is prefixed with % but why is a hash splice prefixed with @ and not %?

my %hash = (
   1 => 'one',
   2 => 'two',
   3 => 'three',
   4 => 'four',
   5 => 'five',
);

print "@hash{'2', '3'}\n";
# prints two three
[download]

Hope someone can enlighten me.

Thanks in advance.

Comment on array splice vs hash splice Select or Download Code

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Re: array splice vs hash splice by chas (Priest) on Jun 05, 2005 at 02:37 UTC
It's actually a "slice". @ is used because the returned value is a list. (A hash is not really printable in its native form - only the associated list is printable in a way readable by humans. That's probably why hashes don't interpolate in double quoted strings - it doesn't make much sense.) chas	[reply]
Re: array splice vs hash splice by Zaxo (Archbishop) on Jun 05, 2005 at 03:14 UTC
Expanding on chas's excellent reply, a hash slice is a list of values from the hash. It is just as suitable for assignment to an array as keys or values, and just as unsuitable for assignment to a hash. After Compline, Zaxo	[reply]
Re: array splice vs hash splice by brian_d_foy (Abbot) on Jun 05, 2005 at 03:26 UTC
I tell my students, and they typically don't have problems recognizing what is what when they think of it this way: When you see a $, you're dealing with one thing. When you see a @, you are dealing with zero or more things. You tell the variable type by what comes after it (nothing in scalars, square braces for arrays, braces for hashs). Sadly, this is going to change in Perl 6. -- brian d foy <brian@stonehenge.com>	[reply]


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