How to Sort Arrays and Data in PHP?

How can I sort arrays and data in PHP?

Basic One Dimensional Arrays

This includes multidimensional arrays, including arrays of objects, and sorting one array based on another.

Sorting Functions:

• sort
• rsort
• asort
• arsort
• natsort
• natcasesort
• ksort
• krsort

Multi Dimensional Arrays, Including Arrays of Objects

PHP requires a custom comparison function to sort complex values.

Steps:

1. Create a comparison function that takes two elements and returns:

   • 0 if the elements are equal.
   • A value less than 0 if the first value is lower.
   • A value greater than 0 if the first value is higher.

2. Use one of these functions:

   • usort
   • uasort
   • uksort

Custom Numeric Comparisons

If sorting by a numeric key:

function cmp(array $a, array $b) {
    return $a['baz'] - $b['baz'];
}

Objects

If sorting an array of objects:

function cmp($a, $b) {
    return $a->baz - $b->baz;
}

Sorting by Multiple Fields

For primary sorting by one field (e.g., "foo") and secondary sorting by another (e.g., "baz"):

function cmp(array $a, array $b) {
    if (($cmp = strcmp($a['foo'], $b['foo'])) !== 0) {
        return $cmp;
    } else {
        return $a['baz'] - $b['baz'];
    }
}

Sorting into a Manual Order

To sort into a specific order (e.g., "foo", "bar", "baz"):

function cmp(array $a, array $b) {
    static $order = array('foo', 'bar', 'baz');
    return array_search($a['foo'], $order) - array_search($b['foo'], $order);
}

Sorting One Array Based on Another

To sort one array based on another:

array_multisort($array1, $array2);

Array_column

As of PHP 5.5.0, you can use array_column to extract a specific column and sort the array accordingly:

array_multisort(array_column($array, 'foo'), SORT_DESC, $array);

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