Software Engineering

How to Divide an Array into Chunks in PHP


If you have a single-dimensional array, and want to break it into chunks, you can use the array_chunks method.

It takes 3 arguments:

  1. The input array / original array
  2. The length of the new array (how many dimensions to create)
  3. A boolean to preserve the original keys or not

<strong>array_chunk</strong>(array&nbsp;$array,&nbsp;int&nbsp;$length,&nbsp;bool&nbsp;$preserve_keys=<strong>false</strong>&nbsp;):array

An example of dividing an array into chunks

Let’s take an initial starter array with 5 values

$input_array = array('a', 'b', 'c', 'd', 'e');

If we said we would like to create 2 chunks:

$new_array = array_chunk($input_array, 2);
print_r($new_array);

/*
Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )
    [1] => Array
        (
            [0] => c
            [1] => d
        )
    [2] => Array
        (
            [0] => e
        )
)
*/

So now let’s try it with preserving the keys:

$new_array =  array_chunk($input_array, 2, true);
print_r($new_array);

/*
Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )
    [1] => Array
        (
            [2] => c
            [3] => d
        )
    [2] => Array
        (
            [4] => e
        )

)
*/

But where would I use this?

This is particularly helpful when constructing tables into HTML renders, or when needing to populate rows and columns when using Bootstrap css col-x-x blocks:

$values = range(1, 31);
$rows = array_chunk($values, 7);

print "<table>\n";
foreach ($rows as $row) {
    print "<tr>\n";
    foreach ($row as $value) {
        print "<td>" . $value . "</td>\n";
    }
    print "</tr>\n";
}
print "</table>\n";