Sorting Arrays

PHP has several functions that deal with sorting arrays, and this document exists to help sort it all out.

The main differences are:

• Some sort based on the array keys, whereas others by the values: $array['key'] = 'value';
• Whether or not the correlation between the keys and values are maintained after the sort, which may mean the keys are reset numerically (0,1,2 ...)
• The order of the sort: alphabetical, ascending (low to high), descending (high to low), natural, random, or user defined
• Note: All of these sort functions act directly on the array variable itself, as opposed to returning a new sorted array
• If any of these sort functions evaluates two members as equal then they retain their original order. Prior to PHP 8.0.0, their order were undefined (the sorting was not stable).