handling printf 0 error

madM has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks, Im trying to run a code of mine .. but every time i run it i get the error

Use of uninitialized value in printf at aprende3.pl line 590
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I know that the error occurs when in the hash of hashes $A->{$key}->{$key2} the program encounters a 0 as value in $key2.. how can i skip that warning? any help would be really appreciated

foreach my $key (@aminos) {
        print OUT $key,' ';
        foreach my $key2 (@aminos ) {
            printf OUT ("$forprint " , $A->{$key}->{$key2});
            }
        }
    }
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Re: handling printf 0 error by Anonymous Monk on Apr 29, 2014 at 10:41 UTC
TIMTOWTDI, it also depends on exactly which of the values you're trying to print is `undef` - since I can't tell from your post I'm going to guess it's `$A->{$key}->{$key2}`, but if not, you will need to adjust the tests in the code examples below accordingly. Solution 1: Disable those warnings altogether. Note that warnings can be useful in debugging, so this may not be the best unless you know what you're doing. `# ... foreach my $key2 (@aminos) { no warnings 'uninitialized'; printf OUT ("$forprint ", $A->{$key}->{$key2}); } # ...` [download] Solution 2: Don't print at all if the value is not defined. `foreach my $key2 (@aminos) { printf OUT ("$forprint ", $A->{$key}->{$key2}) if defined $A->{$key}->{$key2}; }` [download] Solution 3: Use the defined-or operator `//` to replace the undef value with the empty string. (Only available in Perl 5.10 and above) `foreach my $key2 (@aminos) { printf OUT ("$forprint ", $A->{$key}->{$key2} // ''); }` [download] Solution 4: Skip the loop iteration entirely if the value is undefined. (similar idea to Solution 2) `foreach my $key2 (@aminos) { next unless defined $A->{$key}->{$key2}; printf OUT ("$forprint ", $A->{$key}->{$key2}); }` [download]	[reply] [d/l] [select]
Re^2: handling printf 0 error by madM (Beadle) on Apr 29, 2014 at 10:50 UTC
thankyou! that really helped!	[reply]
Re: handling printf 0 error ( how can i skip that warning? Use of uninitialized value in printf ) by Anonymous Monk on Apr 29, 2014 at 10:31 UTC
Two options, make sure to provide a defined value (its SMOP), just as splain/diagnostics/perldiag explains Or disable uninitialized warnings with the warnings pragma `no warnings 'uninitialized';` 0 nodes for skip warning	[reply] [d/l]