Hash of multidimensional array

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

Hi:

I want to know how can I access a Hash of Multidimensional array.
I created the hash from a database:

while ($aref = $sth->fetch)
{
    push @{ $HoA{$l} } , [ $aref->[0] , $aref->[1]  ];
}
[download]

How can I access with a foreach the first elements that are in the array of $HoA{$key}.

Comment on Hash of multidimensional array Download Code

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Re: Hash of multidimensional array by buckaduck (Chaplain) on Mar 16, 2001 at 03:37 UTC
I assume that you realize you are creating a hash with only one key/value pair in this code. Maybe that makes sense in a larger program. For your sake I hope so. If so, you can (for example) access the first bottom-level array reference via: `$HoA{$key}[0]` and the first element in that array via `$HoA{$key}[0][0]` buckaduck	[reply] [d/l] [select]
Multidimensional array not a hash of, I think. by frankus (Priest) on Mar 16, 2001 at 16:57 UTC
Could you clarify: You refer to the item as a hash of arrays when it appears to be a hash of array names. What is the point of having a seperate array of arrays for each key? Why not have a hash of an array of arrays? `$HoA{$key}-[$sth->fetch()]` Any hoo.. To access the first element of an array with the name given by $HoA{$key} which refers to an array of arrays:`${$HoA{$l}}[0]->[0];` The method to reference the hash of arrays is `$HoA{$key}->[0]` My chance to waggle my finger and be boring In SQL: rows even in sequence only have an arbitrary value in a hash, unless you're using a field as the key. $aref is an array reference to an array of arrays (rows x fields) since `fetch` is an alias for `fetchrow_arrayref`, so why dereferencing it? It's make sense if there are more rows in the SQL being returned than you need, however this is wasteful - rewrite the SQL. -- Brother Frankus. Me: Curse you buckaduck for writing so tersely, I repeated your erm.. stuff and made me look dumb. Brain: You made yourself look dumb. Me: You mean I'm really good at something? Woo hoo!!	[reply] [d/l] [select]