in reply to Hash problem


use strict; 
my %hash;

foreach(<DATA>)
{
    $hash{$1}=() if /JSESSIONID=(.*)$/;
}
foreach (sort keys %hash) { print $_."\n"; }

__DATA__

[17/May/2005:18:15:59 -0700]sdjhsj USERID=t70xvcy; jdhdh JSESSIONID=00
+00RDnYTABcRWOx0UN2Zq--sZB:10f408hdg
[17/May/2005:18:15:59 -0700]sdjhsj USERID=t70xvcy; jdhdh JSESSIONID=00
+00RDnYTABcRWOx0UN2Zq--sZB:10f408hdg
[17/May/2005:18:15:59 -0700]sdjhsj USERID=t70xvcy; jdhdh JSESSIONID=00
+00RDnYTABcRWOx0UN2Zq--sZB:10f408g13

[download]


Cheers,
Rupesh.

Replies are listed 'Best First'.
Re^2: Hash problem
by bart (Canon) on May 19, 2005 at 09:24 UTC
    I am amazed that
    $hash{$1}=()
    works without warning, on 5.6.1 and on 5.8.4, as does 
    my $x = ();

    [download]

    Can anybody explain, are my expectations so off?

[reply]
[d/l]
[select]

      From perldata:

      If you evaluate an array in scalar context, it returns the length
      of the array. (Note that this is not true of lists, which return the last
      value, like the C comma operator, nor of built-in functions, which
      return whatever they feel like returning.)

      An empty list doesn't have any values, so trying to get the last value gives you undef.

      We're not surrounded, we're in a target-rich environment!
[reply]

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