Re^2: 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;
[download]

cheers,

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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. —Brad "Don't ever take a fence down until you know the reason it was put up. " G. K. Chesterton	[reply]
Re^4: To initialise or not to initialise? by kiat (Vicar) on Jun 24, 2004 at 13:52 UTC
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` [download] :)	[reply] [d/l]