Re: adding elements to already exisiting elements in an array

Without going in depth to your code, I can think of two ways of doing that:

push @list, $element unless grep {$_ eq $element} @list;

#or 

keys %hash = @list;
$hash{$element}++ unless exists $hash{$element};
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Re^2: adding elements to already exisiting elements in an array by Narveson (Chaplain) on May 14, 2008 at 22:29 UTC
Did you mean `@hash{@list} = ();`? `keys %hash = @list` is legal, but all it does is preallocate storage, it does not actually create any keys for `%hash`. `use strict; use warnings; my @list = qw(A B C); my %hash; keys %hash = @list; for my $element ( qw(D A) ) { $hash{$element}++ unless exists $hash{$element}; } my @new_list = keys %hash; print "Keys are @new_list.\n"; # now insert @list @hash{@list} = (); @new_list = keys %hash; print "Keys are @new_list.\n";` [download]	[reply] [d/l] [select]

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Re^2: adding elements to already exisiting elements in an array
by Narveson (Chaplain) on May 14, 2008 at 22:29 UTC

Did you mean @hash{@list} = ();?

keys %hash = @list is legal, but all it does is preallocate storage, it does not actually create any keys for %hash.

use strict;
use warnings;
my @list = qw(A B C);
my %hash;
keys %hash = @list;
for my $element ( qw(D A) ) {
    $hash{$element}++ unless exists $hash{$element};
}
my @new_list = keys %hash;
print "Keys are @new_list.\n";

# now insert @list
@hash{@list} = ();
@new_list = keys %hash;
print "Keys are @new_list.\n";
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