"Multidimensional Associative Arrays" <<<--- do they exist ?

[Q]

Greetings.

Is there such a thing as mutlidimensional associative array ?

The reason I ask this is that I intent copy the contents of a time stamped file into 
one big file which will be used to update fields of a database. I intend using the 
filename ( remember it is time stamped) and use it as a key.

FILE 1 ( Filename = 23_59_54_20_08_2002)
=

FIELD1FIELD2FIELD3
204060


FILE 2 (Filename = 23_59_55_20_08_2002)
=

FIELD1FIELD2FIELD3
302045


@myFileNameArray = (23_59_54_20_08_2002, 23_59_55_20_08_2002);
@myMultiDimArray = ([20, 40, 60], [30, 20, 45]);

I guess what I am really asking here is can i combine the two arrays in such a way 
that the Filename array becomes the key whose value is mapped to the multidimensioal 
array ?

I hope what i am asking makes sense.

ICQ : 165709889

Re: "Multidimensional Associative Arrays" <<<--- do they exist ?

[Felix Geerinckx]

on Tue, 27 Aug 2002 11:20:32 GMT, [EMAIL PROTECTED] (Q) wrote:

> @myFileNameArray = (23_59_54_20_08_2002, 23_59_55_20_08_2002);
> @myMultiDimArray = ([20, 40, 60], [30, 20, 45]);
> 
> I guess what I am really asking here is can i combine the two
> arrays in such a way that the Filename array becomes the key whose
> value is mapped to the multidimensioal array ? 

Do you perhaps mean:

my %files = ();
$files{'23_59_54_20_08_2002'} = [20, 40, 60];
$files{'23_59_55_20_08_2002'} = [30, 20, 45];

Or are there multiple lines in each file, in which case you could use

$files{'23_59_54_20_08_2002'} = [[20, 40, 60], [70, 80, 90]];

You also may want to turn around your filename, so the year comes 
first, especially when you want to sort (e.g. to iterate from old to 
new).

-- 
felix

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Re: "Multidimensional Associative Arrays" <<<--- do they exist ?

[Michael Lamertz]

On Tue, Aug 27, 2002 at 01:20:32PM +0200, Q wrote:
> Greetings.
> 
> Is there such a thing as mutlidimensional associative array ?
> 
> FILE 1 ( Filename = 23_59_54_20_08_2002)
> =
> 
> FIELD1FIELD2FIELD3
> 204060
> 
> 
> FILE 2 (Filename = 23_59_55_20_08_2002)
> =
> 
> FIELD1FIELD2FIELD3
> 302045

You already got an answer from Felix, but let me feed you a bit more
information as base-knowledge:

perldoc perldsc

Read the "Perl Data Structures Cookbook".  There you'll find a nice
overview about the stuff you need.

perldoc perlref

goes into far more detail, so take a look at that too.


You can take your approach and build a hash of hashes

my $stuff = {
'23_59_54_20_08_2002' => {
field1  => 20,
field2  => 40,
field3  => 60,
},
'23_59_55_20_08_2002' => {
field1  => 30,
field2  => 20,
field3  => 45,
}
}

my $value = $stuff->{$fname}{field2};   # gives '40'

or you could create an array of hashes:

my $stuff = [
{
filename=> '23_59_54_20_08_2002',
data=> {
field1 => ...
}
},
{
filename=> '23_59_55_20_08_2002',
data=> {
...
}
}
}

my $value = $stuff->[0]{field2} # gives '40'

For both methods, You could store the data in an array if the fieldnames
are of no interest to you:

my $stuff = {
'23_59_54_20_08_2002' => [ 20, 40, 60 ],
...
]

my $value = $stuff->{23_59_54_20_08_2002}[2]# guess what

and

my $stuff = [
{
filename=> '23_59_54_20_08_2002',
data=> [ 20, 40, 60 ],
}, 
...
];

my $value = $stuff->[0][1]; # ditto

It all depends on what you want to do with the final data.  Do you want
to easily access single elements?  That would be a candidate for hashes.

Do you want to iterate over your data to calculate statistics?  Smells
like arrays...


And always remember:  When it comes to complex data structures,
Data::Dumper is your friend...


-- 
Well, then let's give that Java-Wussie a beating... (me)

Michael Lamertz| +49 2234 204947 / +49 171 6900 310
Sandstr. 122   |   [EMAIL PROTECTED]
50226 Frechen  | http://www.lamertz.net
Germany|   http://www.perl-ronin.de 

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Re: "Multidimensional Associative Arrays" <<<--- do they exist ?

[Omanakuttan]

$myhash {"23_59_54_20_08_2002"} = [30,20,45] ;
my $x = $myhash{"23_59_54_20_08_2002"},"\n" ;
for my $i (0..$#{$x}) {
 print $myhash{"23_59_54_20_08_2002"}->[$i]," " ;
}
print "\n" ;

HTH.
Om.


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