http://www.perlmonks.org?node_id=130852


in reply to Re: Testing array of hash values
in thread Testing array of hash values

He may have been trying for: 

my %p;
@p{ qw( eyes hair etc ) } = ( undef ) x 3;

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Of course that's crufty in that you have to hard code in the number of elements.

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Re: Another posible initializer
by dvergin (Monsignor) on Dec 11, 2001 at 07:47 UTC
    Actually, 
    my %p;
@p{'eyes', 'hair', 'etc'} = ();

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    is a common idiom for using a hash slice to load a hash with keys and undef values.
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[d/l]

      You're quite right. I was thinking more of: 

      my %p;
@p{ qw( a b c ) } = (1)x3;

      [download]
      where you're initializing to a given value (like 1 or "on") rather than undef.

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[d/l]
[select]
        Yes indeedy. So then, to complete this exercise and return to your very legitimate concern above about maintaining this code if the number of arguments changes, we can use: 
           my %p;
   my @keys = qw( a b c );
   @p{@keys} = (1) x @keys;

        [download]
        and slice assignment will take care of itself if we change the key list.
[reply]
[d/l]

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