in reply to Re: Populating a Hash: Can someone help me to understand?
in thread Populating a Hash: Can someone help me to understand?

You said: 
while (my $key = shift @keys and my $value = shift @values) {
  $hash{$key} = $value;
}

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And your code stops too quickly if either the key or the value is false.
You updated: 
while (defined (my $key = shift @keys) and defined(my $value = shift @
+values)) {
  $hash{$key} = $value;
}

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But even adding the defined test as you did doesn't help. Consider @keys = (1, 2, undef, 3, 4);. You'll never get to 3 or 4.

What would work is: 

while (@keys and @values) {
  $hash{shift @keys} = shift @values;
}

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-- Randal L. Schwartz, Perl hacker

Replies are listed 'Best First'.
RE: RE: Re: Populating a Hash: Can someone help me to understand?
by Limo (Scribe) on Sep 19, 2000 at 19:40 UTC
    Hmmm. Something strange here. 
    my @array = subroutine($file1, $list1);
    #foreach my $item(@array) {
        #print "$item\n";
   # }

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    Now, when I uncomment the foreach/print block, it prints as intended. However, when I add: 
       my %hash;
while (@keys and @values) {
          $hash{shift @keys} = shift @values;
        } 
   
 foreach my $k (sort keys %hash) {
print "$k => $hash{$k}\n";     

 }

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    the program returns only one value per key, while @values contains several whitespace delimited elements.
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[d/l]
[select]
[reply]
        Well, I AM trying to create a hash with multiple values per key! Apparently, this is possible. I'm referring to "Perl Cookbook", pg. 140. There is an example of this, but I'm having a hard time understanding it.
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