Array of hashes reference problem

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

I'm using the following code to process lines in the $discovered array, and create a number of hashed pairs in the same array row. The code works well.

until ($discovered[$i] eq ""){
 ($key, $value) = split /:\s*/, $discovered[$i];
 $arrayAoH[$j]{$key} = $value;
 $i++;
}
[download]

But, when I enabled 'use strict' in my code, I get the following error when the line containing '$arrayAoH[$j]{$key} = $value;' is executed:

"Can't use string ("") as a HASH ref while "strict refs" in use at xxx.pl"

I've pored over the examples in 'Programming Perl', and have Google'd a bit. But I just don't understand why that line is wrong, and what I should do to fix it.

I tried using the following line in place of the offending line:

 $arrayAoH[$j] = { $key => $value };
[download]

but it creates an array row with only a single has (whatever the last has processed was).

Thoughts, please!

Thanks tl

20050623 Edit by ysth: code tags

Comment on Array of hashes reference problem Select or Download Code

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Re: Array of hashes reference problem by tlm (Prior) on Jun 22, 2005 at 17:34 UTC
Where is `$j` defined? What's it's value? It looks like `$arrayAoH[$j]` contains an empty string, not a hash ref. the lowliest monk	[reply]
Re^2: Array of hashes reference problem by tlemons (Novice) on Jun 22, 2005 at 17:52 UTC
Sorry, here's the whole code segment: our @arrayAoH = ""; my $i = 0; # i holds the line number of the input (@discovered) ar +ray. my $j = 0; # j holds the number of the table row. my $key; my $value; # $# returns the subscript of the last element in the array. until ($i eq $#discovered){ if ($discovered[$i] =~ m/Item Number:/){ # parse this line containing labels and values until a blank line is f +ound until ($discovered[$i] eq ""){ ($key, $value) = split /:\s*/, $discovered[$i]; ## $arrayAoH[$j] = { $key => $value }; $arrayAoH[$j]{$key} = $value; $i++; } # If the selected item shouldn't be processed, remove this array row. if (($arrayAoH[$j]{"Model Number"} !~ m/^Foo/)){ splice (@arrayAoH, $j, 1); } else { $j++; } } else { $i++;} } [download] 20050623 Edit by ysth: code tags	[reply] [d/l]
Re^3: Array of hashes reference problem by rev_1318 (Chaplain) on Jun 22, 2005 at 18:15 UTC
here's the whole code segment I doubt that. This code won't parse. When using strict, you have to declare $arrayAoH first. Besides, `$arrayAoH$j{$key} = $value;` [download] should read: `$arrayAoH[$j]{$key} = $value;` [download] and `if (($arrayAoH$j{"Model Number"} !~ m/^Foo/)){` [download] should be `if (($arrayAoH[$j]{"Model Number"} !~ m/^Foo/)){` [download] Please post actual code... Paul	[reply] [d/l] [select]
Re^4: Array of hashes reference problem by tlemons (Novice) on Jun 22, 2005 at 18:30 UTC
Re^3: Array of hashes reference problem by Errto (Vicar) on Jun 23, 2005 at 03:06 UTC
The eventual solution found by sapnac got buried below so I'll re-mention it here with an explanation. The issue is in the "initialization" code `our @arrayAoH = "";` [download] The problem is that this doesn't just create an array. It creates an array with a single element that contains an empty string. It's basically equivalent to `our @arrayAoH; $arrayAoH[0] = "";` [download] The solution is to either leave out the assignment or to assign it an empty list (which is different from an empty string): `our @arrayAoH = ();` [download] More formally, a simple scalar value in list context is treated as a list of length one containing that value.	[reply] [d/l] [select]
Re: Array of hashes reference problem by injunjoel (Priest) on Jun 22, 2005 at 18:04 UTC
Greetings all, Aside from suggesting Data::Dumper or Dumpvalue for complex data-structure investigations I think a read up on perldsc would be worthwhile. However my short answer is to make sure that $key contains something prior to the assignment. -InjunJoel "I do not feel obliged to believe that the same God who endowed us with sense, reason and intellect has intended us to forego their use." -Galileo	[reply]
Re^2: Array of hashes reference problem by tlemons (Novice) on Jun 22, 2005 at 18:20 UTC
Thank you for your reply. I'll re-read the DSC. I just stepped through the code with Komodo, and I'm absolutely sure that both $key and $value have values in them. Does it matter that $key contains a string with a space in the middle (like 'Foo Bar')? Any other suggestions? Thanks tl	[reply]
Re^3: Array of hashes reference problem by sapnac (Beadle) on Jun 22, 2005 at 19:09 UTC
hi! I ran the following code and it executed without error; Please check the input. did not check the result but did not get error when executed; use strict; my $i = 0; <br> my $j = 0; <br> my @discovered;<br> my @arrayAoH;<br> <br> @discovered =(" : hfjfda","rk qjhre:kjfsngfnfd","sdfjlksjf : sfljkhegl +erg"); <br> <br> my $key;<br> my $value;<br> until ($i eq $#discovered){<br> if ($discovered[$i] =~ m/Item Number:/){<br> until ($discovered[$i] eq ""){<br> ($key, $value) = split /:\s*/, $discovered[$i];<br> $arrayAoH[$j]{$key} = $value;<br> $i++;<br> }<br> if (($arrayAoH[$j]{"Model Number"} !~ m/^Foo/)){<br> splice (@arrayAoH, $j, 1);<br> }<br> else {<br> $j++;<br> }<br> }<br> else {<br> $i++;}<br> }<br> [download]	[reply] [d/l]
Re^4: Array of hashes reference problem by tlemons (Novice) on Jun 22, 2005 at 19:38 UTC
Re^5: Array of hashes reference problem by sapnac (Beadle) on Jun 22, 2005 at 20:32 UTC
Some notes below your chosen depth have not been shown here
Re^5: Array of hashes reference problem by djohnston (Monk) on Jun 22, 2005 at 20:29 UTC


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