Contributed by Zombie Arnaud
on Apr 09, 2001 at 13:54 UTC
Q&A
> arrays
Description: I try to find the size of each dimension (sizeX, sizeY, sizeZ) of my 3D array which looks like the following:
$myArray["service1"][0][0]="100";
$myArray["service1"][0][1]="101";
$myArray["service2"][1][2]="212";
...
Answer: How cand I find each dimension x,y,z of a 3D arrays contributed by tilly An important point that nobody has pointed
out:
$myArray["service1"]
will not do what you want. If you want
to look up things by name, you will need a hash.
For learning and playing around with data structures like this I recommend using Data::Dumper so you can easily see what Perl really has done (which may be very different from what you think it is doing). | Answer: How cand I find each dimension x,y,z of a 3D arrays contributed by jeroenes This code will recurse through the elements,
and print the number of array-elements for each
array in your structure. Will not decent hashes
but can be hacked a bit to do that as well.
use strict;
my @a = ([([0..3] ) x 4]) x 3;
arraylength( \@a );
sub arraylength{
my $a = shift;
my $dim = 0;
_length( $a, $dim );
}
sub _length{
my $a = shift;
my $dim = shift;
if ( ref( $a ) =~ /ARRAY/ ){
print "\t" x $dim;
print "dim $dim -> ".(scalar @$a)." elements";
print "\n\n" if $dim == 0;
print "\n" if $dim == 1;
_length( $_, $dim + 1) for ( @$a );
print "\n";
}
}
This example prints:
dim 0 -> 3 elements
dim 1 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 1 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 1 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
dim 2 -> 4 elements
| Answer: How cand I find each dimension x,y,z of a 3D arrays contributed by DrHyde In a perl array of arrays, just like in C, the data structure does not have to be rectangular (or cuboidal, or ...). For example, you can have an array like so:
@foo = (
[0, 1, 2, 3, 4, 5],
[0, 1, 2],
[0, [ 0, 1, 2, 3 ]]
);
There, @foo contains three references to arrays, all of which are of different lengths. One of them contains a reference to another array as well as an ordinary scalar. The following code will tell you the largest number of elements in each dimension. Dimensions are numbered starting at zero (I assume $[ has not been altered):
my @foo = (
[0, 1, 2, 3, 4, 5],
[0, 1, 2],
[0, [ 0, 1, 2, 3 ]]
);
my @maxlength = ();
figger_out_depth(0, @foo);
print "max dimensions:\n";
print " $_: $maxlength[$_]\n" foreach (0..$#maxlength);
sub figger_out_depth {
my $depth = shift;
$maxlength[$depth] = 0 unless(defined($maxlength[$depth]));
foreach my $element (@_) {
figger_out_depth($depth + 1, @{$element}) if(ref($element) eq
+'ARRAY');
}
$maxlength[$depth] = $#_ + 1 if($#_ >= '0'.$maxlength[$depth]);
}
| Answer: How cand I find each dimension x,y,z of a 3D arrays contributed by Anonymous Monk I made this subroutine for work so I guess it's more specific than the other two answers, but I find that this one can be modified and understood far easier than the others:
#this prints 0
print getSecondArraySize("la", %test)."\n";
# put stuff in
$test{"la"}[0] = "1";
$test{"la"}[1] = "2";
$test{"la"}[2] = "3";
#this prints 3
print getSecondArraySize("la", %test)."\n";
And here's the code:
##########################################################
# subroutine getSecondArraySize
# Parameter: An associative array containing scalar
# array and the name of a key
# Returns the total amount of element(s) in the scalar
# array within the associative array at the key location
# index
##########################################################
sub getSecondArraySize {
# receives the argument
my ($index, %array_to_count) = @_;
# create the variable and get the number
my $count=0;
# determine the total amount of elements in the array
while (defined($array_to_count{$index}[$count])) {
$count++;
}
return $count;
}
|
Please (register and) log in if you wish to add an answer
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
|
For: |
|
Use: |
| & | | & |
| < | | < |
| > | | > |
| [ | | [ |
| ] | | ] |
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
|
Log In?
|
|
Chatterbox?
|
How do I use this? | Other CB clients
|
Other Users?
|
Others having an uproarious good time at the Monastery: (5) As of 2021-01-24 13:58 GMT
|
Sections?
|
|
Information?
|
|
Find Nodes?
|
|
Leftovers?
|
|
Voting Booth?
|
|
Notices?
|
|
|