On Tue, Mar 17, 2009 at 8:16 AM, Dermot <paik...@googlemail.com> wrote:
> Hi All,
>
> I am unsure if the following statement is going to do what I want.
>
> I want to test if there is a value in $hash_ref{'someval'} NOT if the
> key is defined. I'd also like to avoid un-sightly "undefined value"
> errors.
Hi Dermot,
It really depends on what the expected/legal values are.
For numeric values, a simple 'if $x{x}' will normally suffice. The
exception is in the case that zero is a legal value, in which case you
need 'defined.' The perldoc exists for a nice rundown.
If there are additional constraints, you really need at least two
tests. Simply testing truth or definiedness will not tell you if the
value is in range, and simply testing the value will throw an error if
the element isn't defined, e.g.
if ( $x{x} and $x{x} =~ /\w+/ ) {}
if ( defined $x{x} and $x{x} > -4 ) {} # 0 is in range, so we
need 'defined'
HTH,
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