trying to populate an array from a hash of arrays

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

Can anyone see what I'm doing wrong below. I'm just trying to populate an array 'mc_mth_attrs' with an array stored in a hash:

 @mc_mth_attrs = @{$mc_attr_lookup{$key}->{attrs}};
 print Dumper(@mc_mth_attrs);
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my error says: Can't use an undefined value as an ARRAY reference

Thanks in advance

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Re: trying to populate an array from a hash of arrays by Zaxo (Archbishop) on Jun 20, 2003 at 13:54 UTC
Try `print Dumper(\@mc_mth_attrs);` Dumper wants a reference to the thing to dunp. If you still have a problem after that, you'll need to show us how `%mc_attr_lookup` is made. After Compline, Zaxo	[reply] [d/l]
Re: trying to populate an array from a hash of arrays by halley (Prior) on Jun 20, 2003 at 13:56 UTC
My 200th post! You didn't include which line has the error, or whether it was a 'warn' or 'carp', so here are both possible reasons: For some value of `$key`, the expression `$mc_attr_lookup{$key}->{attrs}` is undefined. Try dumping `$mc_attr_lookup` first to understand and validate its structure. The `Dumper` routine expects scalars, and some element in `@mc_mth_attrs` is undefined. You probably wanted to do `print Dumper \@mc_mth_attrs;` instead. -- `[ e d @ h a l l e y . c c ]`	[reply] [d/l] [select]
Re: Re: trying to populate an array from a hash of arrays by Anonymous Monk on Jun 20, 2003 at 14:00 UTC
Thanks for the advice....and yes it was a silly mistake. Sorry to have wasted your time with this. Thanks again!	[reply]
Re: trying to populate an array from a hash of arrays by adrianh (Chancellor) on Jun 20, 2003 at 13:56 UTC
Looks like `$mc_attr_lookup{$key}->{attrs}` isn't an array reference. Listen to the code :-) Print it out with Data::Dumper. See what it really is.	[reply] [d/l]