Re^2: Undef and Unitialized Issue

my $string_var = defined( $input_field ) || '';

This will set $string_var either to 1 or to "", no matter what $input_field was set to. Looking at the variable names, this is hardly what you want.

($string_var || '')

This evaluates to "" if $string_var is undef, 0, or "0". You don't want to change "0" or 0 to the empty string, do you?

Why don't you use the defined-or operator //? $string_var//'' evaluates to "" only if $string_var is "" or undef. 0 and "0" are not changed.

Ancient perl versions have no defined-or-operator, so you have to resort to something like $never_undef=defined($perhaps_undef) ? $perhaps_undef : ''; for code that is expected to work with ancient perl verisons.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

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Re^3: Undef and Unitialized Issue by boftx (Deacon) on Apr 06, 2015 at 15:18 UTC
You are correct, I was thinking of where I use `delete($input) \|\| ''` to ensure a defined value and "0" is not a concern. The second form you present (using `?:`) is more correct in the general case. As for using an "ancient version of Perl" I don't have a choice at $work, we are stuck on 5.8.9 for at least a few more months. You must always remember that the primary goal is to *drain the swamp* even when you are hip-deep in alligators.	[reply] [d/l] [select]

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Re^3: Undef and Unitialized Issue
by boftx (Deacon) on Apr 06, 2015 at 15:18 UTC

You are correct, I was thinking of where I use delete($input) || '' to ensure a defined value and "0" is not a concern. The second form you present (using ?:) is more correct in the general case.

As for using an "ancient version of Perl" I don't have a choice at $work, we are stuck on 5.8.9 for at least a few more months.

You must always remember that the primary goal is to drain the swamp even when you are hip-deep in alligators.

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