Re^4: Help choosing the most efficient, dependable condition(al)

Greetings kcott, and thank you for the followup.

My rationale (which might be an oxymoron) was that if I didn't have an Accept value (one wasn't provided). the unless would ensure an "always valid" -- see; defined value. No?

I think this speaks volumes on how I think. Kinda' scary. It's so revealing. :)

Thanks again, for taking the time to respond!

--Chris

#!/usr/bin/perl -Tw
use Perl::Always or die;
my $perl_version = (5.12.5);
print $perl_version;

Comment on Re^4: Help choosing the most efficient, dependable condition(al)

Replies are listed 'Best First'.
Re^5: Help choosing the most efficient, dependable condition(al) by kcott (Archbishop) on Nov 13, 2013 at 20:35 UTC
"My rationale (which might be an oxymoron) was that if I didn't have an `Accept` value (one wasn't provided). the unless would ensure an "always valid" -- see; `defined` value. No?" No! And that's very easy to test: `#!/usr/bin/env perl -l use strict; use warnings; my %test_hash; if ($test_hash{unset_key} =~ /x/) { print 'true'; } else { print 'false'; } unless ($test_hash{unset_key} =~ /x/) { print 'false'; } else { print 'true'; }` [download] Output: `Use of uninitialized value $test_hash{"unset_key"} in pattern match (m +//) at ./pm_example.pl line 8. false Use of uninitialized value $test_hash{"unset_key"} in pattern match (m +//) at ./pm_example.pl line 15. false` [download] Perhaps you want exists and/or defined. -- Ken	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^5: Help choosing the most efficient, dependable condition(al)
by kcott (Archbishop) on Nov 13, 2013 at 20:35 UTC

"My rationale (which might be an oxymoron) was that if I didn't have an Accept value (one wasn't provided). the unless would ensure an "always valid" -- see; defined value. No?"

No! And that's very easy to test:

#!/usr/bin/env perl -l

use strict;
use warnings;

my %test_hash;

if ($test_hash{unset_key} =~ /x/) {
    print 'true';
}
else {
    print 'false';
}

unless ($test_hash{unset_key} =~ /x/) {
    print 'false';
}
else {
    print 'true';
}
[download]

Output:

Use of uninitialized value $test_hash{"unset_key"} in pattern match (m
+//) at ./pm_example.pl line 8.
false
Use of uninitialized value $test_hash{"unset_key"} in pattern match (m
+//) at ./pm_example.pl line 15.
false
[download]

Perhaps you want exists and/or defined.

-- Ken

[reply]
[d/l]
[select]