foreach problem

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

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Re: foreach problem by Fletch (Bishop) on Mar 03, 2009 at 19:21 UTC
That's because in line two you're ~~referring to~~ using the package variable `%lib` when you mean to be dereferencing the hashref you've got: `$lib->{'foo'}`. The cake is a lie. The cake is a lie. The cake is a lie.	[reply] [d/l] [select]
Re: foreach problem by kennethk (Abbot) on Mar 03, 2009 at 19:23 UTC
A reread through perllol or perlreftut might be helpful. When you use the syntax `$libs[$i]{'file'}` it's actually short hand for `$libs[$i]->{'file'}` since each element of `@libs` is a hash reference. The error 'requires explicit package name' is because `$lib{'file'}` is trying to access the 'file' element of the hash `%lib` - the dereference cannot be done automatically due to potential syntactic ambiguity. What would work for you is: `1 foreach my $lib (@libs) { 2 my $file = $lib->{'file'}; 3 print "reading $file\n"; 4 }` [download]	[reply] [d/l] [select]
Re: foreach problem by ikegami (Patriarch) on Mar 03, 2009 at 20:06 UTC
Keep in mind an array of hashes is actually an array of references to hashes. `$libs[$i]{'file'}` [download] is shorthand for `$libs[$i]->{'file'}` [download] so if you replace array element `$libs[$i]` with scalar `$lib`, you get `$lib->{'file'}` [download] `$lib{'file'}` refers to the hash `%lib`.	[reply] [d/l] [select]
Re: foreach problem by zwon (Abbot) on Mar 03, 2009 at 19:23 UTC
`$lib->{'file'}` should work	[reply] [d/l]
Re: foreach problem by glasswalk3r (Friar) on Mar 03, 2009 at 19:25 UTC
Enabling: `use warnings; use strict;` [download] Should do it. This is very basic and you should be using it always. Alceu Rodrigues de Freitas Junior --------------------------------- "You have enemies? Good. That means you've stood up for something, sometime in your life." - Sir Winston Churchill	[reply] [d/l]
Re^2: foreach problem by GrandFather (Saint) on Mar 03, 2009 at 19:56 UTC
Do what pray? The following code (without strictures) `my @libs = qw{1 2 3 4}; foreach my $lib (@libs) { my $file = $lib{'file'}; print "reading $file\n"; }` [download] Prints: `reading reading reading reading` [download] and with use strict added generates the error: `Global symbol "%lib" requires explicit package name at ... line 7. Execution of ... aborted due to compilation errors.` [download] which is the 'requires explicit package name' that worried the OP (and quite rightly). The OP is using strictures and they have just saved his job/his marriage/his sanity/the world, or whatever. Good OP++! True laziness is hard work	[reply] [d/l] [select]