Array ([0] = Array ([0] = a [1] = b) [1] = Array ([0] = c [1] = d) [2] = Array ([0] = e)) Array ([0] = Array ([0] = a [1] = b) [1] = Array ([2] = c [3] = d) [2] = Array ([4] = e))
By setting the optional preserve_keys parameter to TRUE, you can force PHP to preserve the original keys from the input array. If you specify FALSE new number indices will be used in each resulting array with indices starting from zero. The default is FALSE.