Three ways of checking the value in a hash:

if (exists  $hash{$key})  # If exists
if (defined $hash{$key})  # If exists, defined
if (        $hash{$key})  # If exists, defined and true

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If the value is just a flag, then I wouldn't even use defined. I would just treat the value as boolean. It's less verbose, and it works for all three checks listed above.

As for defined vs exists, there isn't really any difference as long as the value can't normally be undefined.

In reply to Re: Hashing it out: defined? exists? by ikegami
in thread Hashing it out: defined? exists? by eff_i_g

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