in reply to sum function

Here. This is definitely NOT shorter, but it is more robust. And unless I'm clueless, using map in a situation like this creates a second array in RAM, which you are throwing away. While this may not be a problem, it does not promote efficient memory management. 
#!/usr/bin/perl -w
use strict;
my %hash = ( foo => '123' , bar => '234',
             batz => '345', bongo => '100' );

#send reference to hash, and list of keys to sum
print sum_hash( \%hash, 'foo', 'bar', 'batz' ) . "\n";

#send reference to hash, will sum all numeric values
print sum_hash( \%hash ) . "\n";

sub sum_hash {
    my $t_hash = shift;
    my $total;
    if (@_) {
        for (@_) {$total += $t_hash->{$_}; }
    }
    else {
        for ( keys %$hashref ) { $total += $t_hash->{$_}; };
    }
    return $total;
}

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Re: Re: sum function
by chipmunk (Parson) on Dec 26, 2000 at 02:21 UTC
    For the else block, it's simpler to iterate over the values() rather than the keys. (Mind the name of the variable...) 
        else {
        for (values %$t_hash) { $total += $_ }
        # (use the statement modifier for if preferred)
    }

    [download]
    The two blocks could also be combined into a single loop -- whether this is an improvement, I'm not sure. :) 
    sub sum_hash {
  my $href = shift;
  my $total = 0;
  for ( @_ ? @{$href}{@_} : values %$href ) {
    $total += $_;
  }
  return $total;
}

    [download]
    If @_ contains any elements, iterate over a hash slice using the contents of @_ as the keys; otherwise iterate over all the values in the hash.
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[d/l]
[select]
      Chipmunk, I love it. Your second method is especially Perlish.
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