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Re^2: To initialise or not to initialise?

by kiat (Vicar)
on Jun 24, 2004 at 13:30 UTC ( #369347=note: print w/replies, xml ) Need Help??

in reply to Re: To initialise or not to initialise?
in thread To initialise or not to initialise?

Hi bradcathey,
I have found there is a difference between:
Do you mean the difference between being defined and undefined?
my $var1; # not printed because $var1 is not defined print "var1: $var1\n" if defined $var1; my $var2 = ''; # printed with $var2 as an empty string # output var2: print "var2: $var2\n" if defined $var2; my $var3 = 0; # printed with $var3 set to 0 # output var3: 0 print "var3: $var3\n" if defined $var3;

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Re^3: To initialise or not to initialise?
by bradcathey (Prior) on Jun 24, 2004 at 13:34 UTC
    Precisely, thanks for clearing up the terminology. And I have to apologize for not being about to think of a good example, but I have found at times I need the undefined variable, as opposed to the defined, inferring a value.

    "Don't ever take a fence down until you know the reason it was put up. " G. K. Chesterton
      Ah okay.

      I thought it might be something to do with concatenation at first, which also shows a subtle difference:

      my $var1; print $var1 .= 'r', "\n"; # prints r my $var2 = ''; print $var2 .= 'r', "\n"; #prints r my $var3 = 0; print $var3 .= 'r', "\n"; #prints 0r

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