PHP Modify an Array within an Array

Question

I created an Array and put the Array inside another Array. I would like to now modify the Array, but the code never does modify it.
Here is the Create Part:

$arr_row_name = array();
for($nrow=0;$nrow < $numRows;$nrow++)
{
    $arr_slot_name = array();
    for($nsp=0;$nsp < $numServProvider + 1;$nsp++)
    {
        $arr_slot_name[] = "Closed";
    }
    //Add Slot to the row.......
    $arr_row_name[] = $arr_slot_name;
}

Here is the part where I try to access the array and modify it.

$arr_row_length = count($arr_row_name);
for($x=0;$x<$arr_row_length;$x++)
{
    $arr_slot_name = $arr_row_name[$x];
    $arr_slot_length = count($arr_slot_name);
    for($slot=0;$slot<$arr_slot_length;$slot++)
    {
        $arr_slot_name[$slot] = "Open";
    }           
}

They say you may get unexpected results if you modify an array while traversing it. It might be better to make a copy of the array. Then, while traversing the original, you alter the copy. Then you overwrite the original with the copy. — Buttle Butkus
– Buttle Butkus, Commented Aug 22, 2014 at 21:32

keithhatfield · Accepted Answer · 2013-08-28 17:52:37Z

1

In your second bit of code, change:

$arr_slot_name = $arr_row_name[$x];

to:

$arr_slot_name = &$arr_row_name[$x];

The way that you have it, you are making a copy of $arr_row_name[$x] into $arr_slot_name ... in the second option, you are assigning it by reference and will be able to change the original ...

answered Aug 28, 2013 at 17:52

keithhatfield

3,2831 gold badge20 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Joe Doran Over a year ago

Ah. I know I was missing something. Thank you.

Collectives™ on Stack Overflow

PHP Modify an Array within an Array

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related