PHP provides multiple functions to sort arrays, and choosing the right one depends on what type of array you have and how you want to organize it.

For indexed arrays (simple lists):

sort() arranges items in ascending order — alphabetically for strings (A to Z) or numerically for numbers (smallest to largest). It modifies the original array directly.

rsort() does the opposite — descending order (Z to A, or largest to smallest). The “r” stands for reverse.

Both functions work on the values and ignore or reset the index numbers.

For associative arrays (key-value pairs):

You have four options because associative arrays have both keys and values, and you might want to sort by either one:

asort() sorts by values in ascending order while keeping the key-value relationships intact. If you have names as keys and ages as values, this sorts by age but preserves which age belongs to which name.

ksort() sorts by keys in ascending order. Same data, but now organized alphabetically by the names instead of numerically by ages.

arsort() and krsort() are the descending versions — same logic, opposite direction. The “r” again means reverse.

Important detail: All these functions modify the original array. They don't return a new sorted array — they change the one you pass in. So if you need to keep the original order, make a copy first.

Why This Matters:

WordPress uses sorted arrays constantly. User lists sorted by registration date, posts sorted by title, menu items sorted by position, plugin settings displayed alphabetically — understanding how to sort data is essential for presenting information clearly and building features that organize content logically.