How to work with multidimensional array?

[deko]

I have 2 arrays (of different length) that I map together like this:

$mapped_array = array_map(null, array_reverse($data_array), array_reverse($counter_array));

I try to get the count of each array in $mapped_array like this:

echo "Starting with ".count($mapped_array[0])." elements in data_array<br>";

echo "Starting with ".count($mapped_array[1])." elements in counter_array<br><br>";

but the count is 0 - am I referencing the arrays properly?

Then I want to remove elements from both arrays based on a match of a particular IP in each element of $mapped_array[0], which is exploded into an array:

for ( $i=0; $i < count($mapped_array[0]); $i++ )
		{
		$data_line = $mapped_array[0][$i];
		$data = explode("|", $data_line);
		if( in_array($ip, $data) )
			{
			array_splice($mapped_array,$i,1);

			}
		}
echo "Ending with ".count($mapped_array[0])." elements in data_array<br>";
echo "Ending with ".count($mapped_array[1])." elements in counter_array<br><br>";

This does not work... where am I going wrong?

Thanks in advance

[paulnaj]

Hi deko,

Haven't used this function before but, according to the manual reference for array_map() ...

'Usually when using two or more arrays, they should be of equal length because the callback function is applied in parallel to the corresponding elements. If the arrays are of unequal length, the shortest one will be extended with empty elements. '

Does that answer your question?

Paul.

[Weedpacket]

So in other words, the number of elements in $mapped_array will be equal to the number of elements in the shorter of $data_array and $counter_array. If one of those is empty, the result will be empty as well.

From what you're doing in the rest of the code, it looks like you don't want array_map at all, just
$mapped_array = array(array_reverse($data_array), array_reverse($counter_array));

[deko]

There's an element-to-element relationship between the two arrays. The idea is to do stuff against a single mapped_array rather than each array individually.

There must be a way to reference an array within an array.

Apparently, count($mapped_array[0]) is not it.

[paulnaj]

Hi deko,

I've just adapted the example in the manual. Notice that I've got $a with 4 elements, $b and $c have three.

Doesn't quite work as I (and maybe Weedacket) expected ...

<?php
$a = array(1, 2, 3, 4);
$b = array("one", "two", "three");
$c = array("uno", "dos", "tres");

$d = array_map(null, $a, $b, $c);
echo '<pre>'; 
print_r($d);
echo '</pre>';

echo '$d has '. count($d).' elements<br>';
for($i = 0; $i < count($d); $i++){
	echo '$d['.$i.'] has '.count($d[$i]).' elements<br>';
}
?>

Still not sure what your problem is ...

Paul.