Re: Array reference error

This probably means that $res{'acts'} is undef, therefore you'll get a warning about trying to treat it like an arrayref. One simple solution is:

@{$res{'act'}} = sort {
        return 0 unless $a->{'act'} =~ /^move/ and $b->{'act'} =~ /^mo
+ve/;
        return $a->{'act'} cmp $b->{'act'};  # add < delete
    } @{ $res{'acts'} or [] };

return \%res;
[download]

The @{ $res{'acts'} or [] } construct will choose $res{'acts'} (if it evaluates to true) or a reference to an empty array (otherwise), and whichever gets chosen, then dereference the arrayref to get an array.

The other easy way is to simply disable that warning before you attempt the sort...

no warnings qw(uninitialized);

@{$res{'act'}} = sort {
        return 0 unless $a->{'act'} =~ /^move/ and $b->{'act'} =~ /^mo
+ve/;
        return $a->{'act'} cmp $b->{'act'};  # add < delete
    } @{$res{'acts'}};

return \%res;
[download]

Warnings are supposed to be helpful. If you're not finding them helpful, there's no point in suffering them.

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

Comment on Re: Array reference error Select or Download Code

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Re^2: Array reference error by AnomalousMonk (Archbishop) on Feb 27, 2014 at 19:32 UTC
There doesn't seem to be an `'undefined'` warning (see perllexwarn), but turning off strict references together with `'uninitialized'` warnings (both of these actions taken within the narrowest possible scope, of course) seems to do the trick. `c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le "my %res; ;; no strict qw(refs); no warnings qw(uninitialized); ;; @{$res{'act'}} = sort { return 0 unless $a->{'act'} =~ /^move/ and $b->{'act'} =~ /^move/; return $a->{'act'} cmp $b->{'act'}; } @{$res{'acts'}}; dd \%res; " { act => [] }` [download]	[reply] [d/l] [select]
Re^3: Array reference error by tobyink (Canon) on Feb 27, 2014 at 22:39 UTC
Oops, yes. I meant `uninitialized`. Fixed. Turning off strict refs should not be necessary for this. `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply] [d/l]
Re^4: Array reference error by AnomalousMonk (Archbishop) on Feb 28, 2014 at 19:22 UTC
For this particular example, `no strict 'refs';` seems to be essential. (Checked under both ActiveState 5.8.9 and Strawberry 5.14.4.1) `c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le "my %res; ;; no warnings qw(uninitialized); ;; @{$res{'act'}} = sort { return 0 unless $a->{'act'} =~ /^move/ and $b->{'act'} =~ /^move/; return $a->{'act'} cmp $b->{'act'}; } @{$res{'acts'}}; dd \%res; " Can't use an undefined value as an ARRAY reference at -e line 1.` [download]	[reply] [d/l] [select]