On 3/25/11 Fri Mar 25, 2011 11:15 AM, "Chris Stinemetz"
<[email protected]> scribbled:
> I am getting the warning:
>
> Argument "" isn't numeric in numeric lt (<) at ./DOband.pl line 22,
> <$fh> line 52411.
>
> It seems to be directed to the below ternary operator:
> How can I include in the ternary to ignore all non numeric values in
> the elements $cell and $chan?
>
> my $carr =
>
> ( $cell < 299 && $chan == 175 ) ? 2 :
> ( $chan == 1025 ) ? 2 : 1 ; #nested ternary operator
>
According to the error message, $cell contains "", the empty string. Perl is
objecting to the attempt to compare that value with 299. The solution is to
either 1) don't attempt the comparison if $cell is an empty string or 2) set
$cell to a valid numerical value if it contains an empty string.
For the former case, you can use an if statement:
if( $cell ) {
...
but that will eliminate cases where $cell has a possibly valid value of
zero.
For the latter case, the value zero is a natural substitute, but only you
can say if this is a valid thing to do in your situation. The normal way to
do this is:
$cell = $cell || 0;
This assigns numerical zero to $cell if it's current value evaluates to
false (undef, 0, or ''). This may be shortened to:
$cell ||= 0;
This substitution can also be done in some cases when a value is assigned to
the variable, e.g.:
$cell = $data[1] || 0;
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