2 dimensional array

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

Ok let me ask the question again, I dont think I was clear enough in explaining what I need :( I have a list of $a $b values which can go from (-180 --- 180)

For example:
100 2
-2  44
332 9
26  -4
332 9
0   -1
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I want to creat a 2 dimentional array 360x360 and set it to zero then start recording the count of combnation $a $b the combanation of 332 and 9 appered twice on the list so the count will be 2

my @a = ((0) x 361);

my @b = ((0) x 361);

my @matrix = (@a,@b)

while ($line = <IN>)
{
@record   = split(/\s+/, $line);
$a = $record[0]; 
$b  = $record[1]; 
@matrix [$a+180][$b+180] ++;
}
[download]

and Yes Ikegami you are right I do understand now why 361 :) thanks

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Re: 2 dimensional array
by ikegami (Patriarch) on Jul 28, 2011 at 19:43 UTC

Original content of parent

Hi,

I have a list of 2 variable $a $b $a can be from -180 up to 180 $b also can be from -180 up to 180 I want to create a 360 x 360 array and fill it with zeros then go throw the list and record the counts of the combination of $a and $b (i.e. every time I find a combination of 2 4 I will add +1 to the count)

For example a list of:

3 0
1 2
2 4
3 0
3 3
2 4


  0 1 2 3 4
0 0 0 0 2 0
1 0 0 0 0 0
2 0 1 0 0 0
3 0 0 0 1 0
4 0 0 2 0 0
[download]

Could you please help me? I don’t know how to start :s

Thx

I think you mean 361 x 361. Arrays must have non-negative indexes, so just store everything 180 indexes higher.

$a[$row][$col]
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$a[$row + 180][$col + 180]
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Re: 2 dimensional array
by ww (Archbishop) on Jul 28, 2011 at 22:25 UTC

"Ok let me ask the question again...."

We're always glad to have clarification of a question, but please, do so by editing (using <strike>...</strike>) and appropriate labeling to indicate what's new (if it's changed, we can tell from your strikeouts).

But, please, don't start a new thread (create a new rootnode) to correct or clarify. Often as not, that merely confuses readers as to which thread you really care about.