I am solving a larger problem and at one step I need to rotate a 2D array counter-clockwise.
So if I have this matrix:
JavaScript
x
1 2 3 4
1 2 3 4
3 4 5 6
3 4 5 6
After the rotation it will be:
JavaScript
4 4 6 6
3 3 5 5
2 2 4 4
1 1 3 3
I have found a solution to rotate it clockwise:
JavaScript
<?php
$a = array(array(1,2,3,4),array(5,6,7,8),array(9,0,1,2),array(3,4,5,6));
$b = array(); //result
while(count($a)>0)
{
$b[count($a[0])-1][] = array_shift($a[0]);
if (count($a[0])==0)
{
array_shift($a);
}
}
?>
The thing is that this has to work even when a
is uni-dimensional or has only one element.
So, 1 2 3 4
will become:
JavaScript
4
3
2
1
Advertisement
Answer
JavaScript
$b = call_user_func_array(
'array_map',
array(-1 => null) + array_map('array_reverse', $a)
);
I’ll leave it as an exercise for the reader to figure out how it works.