foreach (@array){ print "$_\n"; } foreach (sort keys %hash){ print "$_ $hash{$_}\n"; }
For the past couple of days I have been working on a piece of code that I just could NOT figure out why I was getting "Use of uninitialized value....". I used the snippet above several times. I wrote short scripts to prove to myself my code was working. Yet, in the actual script, the same code would not work.
My hash looked something like this:
I struggled with this for a couple of days trying to see what was going on. Why was I getting this mysterious 'undef'. I thought about using Data::Dumper as I had seen so many times here. But I didn't get around to it until today.1111 Fred 2222 Wilma 3333 Barney 4444 Betty
I put in Data::Dumper::Simple and within 2 minutes saw the issue. My data that I thought looked like the above, really looked more like this:
'1111 ' -> 'Fred' '2222 ' -> 'Wilma' '3333 ' -> 'Barney' '4444 ' -> 'Betty'
There was a trailing space in my keys. I would probably have never located this problem without Data::Dumper.
Data::Dumper(::Simple) is my new friend
I guess lessons learned the hard way are the ones you remember most easily.
M
Update: Thanks itub and Nkuvu. Both very good points. Using delimiters around the variables is an excellent idea that I will remember. Thanks.
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