Re^3: Autovivification sucking the life out of me

Update: My apologies! Forget what I have said, it was my observation was off, not yours. But it might be a better idea to demo your issue by using Data::Dumper.

use Data::Dumper;

use strict;
use warnings;
my  %foo = ( BAZ => 1 );
sub see_args { };

print Dumper(\%foo);
see_args( @foo{qw(BAR BAZ)} );
print Dumper(\%foo);
[download]

It prints:

$VAR1 = {
          'BAZ' => 1
        };
$VAR1 = {
          'BAZ' => 1,
          'BAR' => undef
        };
[download]

Yes, autovivification is in working.

Your observation was off. In your original post, you were confused by the fact that the $ENV{TMPDIR} "appears" to have a value as you saw it through that sprintf. No, you didn't see the value of $ENV{TMPDIR}. Your sprintf printed a constant "<absent>", not the value of $ENV{TMPDIR}.</strick>

Comment on Re^3: Autovivification sucking the life out of me
Select or Download Code

Replies are listed 'Best First'.

Re^4: Autovivification sucking the life out of me
by shenme (Priest) on Oct 14, 2005 at 07:11 UTC

use strict;
use warnings;
my  %foo = ( BAZ => 1 );
sub see_args { };

    warn sprintf "at start: BAR '%s'\n",
        ! exists $foo{BAR} ?  '<absent>' : ! defined $foo{BAR} ? '<und
+ef>' : $foo{BAR};

#   see_args( @foo{qw(BAR BAZ)} );
    my @a = @foo{qw(BAR BAZ)};

    warn sprintf "at end: BAR '%s'\n",
        ! exists $foo{BAR} ?  '<absent>' : ! defined $foo{BAR} ? '<und
+ef>' : $foo{BAR};
[download]

Running this without the subroutine call, but rather the assignment to the array, results in output:

at start: BAR '<absent>'
at end: BAR '<absent>'
[download]

@foo{qw(BAR BAZ)}

Commenting out the assignment and instead executing the subroutine call produces this output:

at start: BAR '<absent>'
at end: BAR '<undef>'
[download]

[reply]
[d/l]
[select]


P is for Practical
	PerlMonks