Re^2: Different result for 'foreach' vs 'while shift' arrayref

And I think this, while breaking the mental encapsulation of the single line versions, might be easier for some hackers to grok. No personal preference here; just tossing one more on the pile.

while ( @{$rowcache} ) {
    my $result = shift @{$rowcache};
    ....
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Re^3: Different result for 'foreach' vs 'while shift' arrayref by tobyink (Canon) on Apr 19, 2014 at 09:29 UTC
That's certainly true. I often use that, and have no idea why I didn't suggest it myself! Generally speaking the reason to use this idiom is when you need to loop through a list and in each iteration you need to take one or more items from the list.This kind of thing: `use strict; use warnings; use Data::Dumper; my @input = ( 'foo:' => 1, 'bar:' => 2, 'baz', # no colon, so value is "1" 'quux:' => 3, ); my %output; while (@input) { my $key = shift @input; if ($key =~ /\A(.+):\z/) { $output{$1} = shift @input; } else { $output{$key} = 1; } } print Dumper \%output;` [download] If you only need to step through the list one at a time, use `foreach`; it's clearer. `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply] [d/l] [select]

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Re^3: Different result for 'foreach' vs 'while shift' arrayref
by tobyink (Canon) on Apr 19, 2014 at 09:29 UTC

That's certainly true. I often use that, and have no idea why I didn't suggest it myself!

Generally speaking the reason to use this idiom is when you need to loop through a list and in each iteration you need to take one or more items from the list.This kind of thing:

use strict;
use warnings;
use Data::Dumper;

my @input = (
    'foo:'   => 1,
    'bar:'   => 2,
    'baz',  # no colon, so value is "1"
    'quux:'  => 3,
);

my %output;
while (@input)
{
    my $key = shift @input;
    
    if ($key =~ /\A(.+):\z/)
    {
        $output{$1} = shift @input;
    }
    else
    {
        $output{$key} = 1;
    }
}

print Dumper \%output;
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If you only need to step through the list one at a time, use foreach; it's clearer.

use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name

[reply]
[d/l]
[select]