On Sat, 2002-03-02 at 11:16, John Crockett wrote:
> I'm sure this is such a simple thing, most of you-all are laughing at me
> right now.
>
> main_program
> {
> blah;
> blah;
>
> %input_parm = ();
> $input_parm{PRICE} = "42.00";
> $input_parm{PRODUCT_ID} = "1306";
> $input_parm{INVENTORY_LOC} = "107";
> $input_parm{CUSTID} = "23489";
>
> my_subroutine(%input_parm);
>
> more irrelevant code;
> .
> .
> .
> }
>
>
> sub my_subroutine(%)
> {
> This is where I have trouble. I can't figure out the notation for
> reading the hash!
> }
>
>
> Thanks for your help.
>
> John Crockett
> [EMAIL PROTECTED]
>
> (Take out NoSpam to e-mail me)
Firstly, you must declare prototypes _before_ you use them or they will
have no effect.
Secondly, you should rarely, if ever, use prototypes. They are a nasty
bit of magic that is poorly understood by many and not yet needed by
most.
Instead use one of the following two methods:
When a hash is evaluated in a list context it is transformed into a list
of alternating of keys and values. The constructor for a hash takes a
list of (key, value) pairs. So the code to pass a hash looks like this:
<example>
#!/usr/bin/perl
use strict;
my %hash = (
key1 => 'value 1',
key2 => 'value 2',
key3 => 'value 3',
);
print_hash(%hash);
sub print_hash {
my %hash = @_;
foreach my $key (sort keys %hash) {
print "$key => $hash{$key}\n";
}
}
</example>
There are two problems with passing hashes this way: it takes time to
decompose and rebuild the hash and the hash eats all of the parameters.
So people often use references like this:
<example>
#!/usr/bin/perl
use strict;
my %hash = (
key1 => 'value 1',
key2 => 'value 2',
key3 => 'value 3',
);
print_hash(\%hash, '=>');
sub print_hash {
my ($hash, $connector) = @_;
foreach my $key (sort keys %$hash) {
print "$key $connector $$hash{$key}\n";
}
}
</example>
--
Today is Sweetmorn the 61st day of Chaos in the YOLD 3168
Missile Address: 33:48:3.521N 84:23:34.786W
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
