On 17/09/2014 01:37, SSC_perl wrote:
I just ran across something puzzling. Why are these two statements
not equivalent when it comes to warnings?
if ($item->{'optionprice'}) {
$item->{'unitprice'} += $item->{'optionprice'};
}
and
$item->{'unitprice'} += $item->{'optionprice'} if ($item->{'optionprice'});
Given the following values:
$item->{'unitprice'} = '12.16';
$item->{'optionprice'} = '';
the 2nd statement returns an "Argument '' isn't numeric in addition
(+)" warning, while the 1st one doesn't.
I thought I read where Peal reads a statement like the 2nd one from
right to left. It looks like it doesn't, since $item->{'optionprice'}
is evaluated in spite of the 'if'.
Am I mistaken?
Perl 5.10.1
As you have presented them, those code fragments are identical in
meaning. The code I used to prove it is below, and it give the output
{ optionprice => "", unitprice => 12.16 }
which is unchanged from the initial settings.
The probable error I can see is that, even if `$item->{optionprice}` is
true, it need not be numeric, and so would raise the `not numeric` warning.
Rob
use strict;
use warnings;
use 5.010;
my $item;
$item->{unitprice} = '12.16';
$item->{optionprice} = '';
if ($item->{optionprice}) {
$item->{unitprice} += $item->{optionprice};
}
$item->{unitprice} += $item->{optionprice} if ($item->{optionprice});
use Data::Dump;
dd $item;
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