Introduction

Sorting an array alphabetically in PHP is usually a one-function task, but the right function depends on whether the array is indexed or associative and whether key order must be preserved. The important part is choosing the sorting function that matches the data structure and the output you need.

Sort Indexed Arrays with sort

If the array is a plain indexed list and you only care about sorting values alphabetically, use sort().

1<?php
2$fruits = ["banana", "apple", "orange"];
3sort($fruits);
4print_r($fruits);

After sorting, the values are in ascending alphabetical order and the numeric keys are reindexed.

This is the simplest and most common answer for plain lists.

Preserve Keys with asort

If the array is associative and you want to sort by value while keeping the original keys, use asort().

1<?php
2$users = [
3    "u3" => "Charlie",
4    "u1" => "Alice",
5    "u2" => "Bob",
6];
7
8asort($users);
9print_r($users);

This keeps the key-value relationship intact, which matters if the keys are meaningful identifiers.

Sort by Key with ksort

Sometimes the question sounds like value sorting, but the real need is alphabetical ordering of the keys instead.

1<?php
2$users = [
3    "charlie" => 30,
4    "alice" => 25,
5    "bob" => 28,
6];
7
8ksort($users);
9print_r($users);

That sorts by the key names rather than the stored values.

Case Sensitivity Matters

PHP's basic sorting functions compare strings in a way that may not match human expectations when upper and lower case are mixed. If you want a case-insensitive alphabetical sort, use usort() or uasort() with strcasecmp().

1<?php
2$names = ["banana", "Apple", "orange"];
3
4usort($names, 'strcasecmp');
5print_r($names);

This often produces a more natural alphabetical result for user-facing text.

Sort Arrays of Records by a String Field

If your data is an array of arrays or objects, define the sort rule explicitly.

1<?php
2$items = [
3    ["name" => "Charlie"],
4    ["name" => "Alice"],
5    ["name" => "Bob"],
6];
7
8usort($items, function ($a, $b) {
9    return strcmp($a["name"], $b["name"]);
10});
11
12print_r($items);

This is much clearer than trying to reshape the data just to use sort().

Locale-Aware Sorting Is a Different Problem

If the text includes accented characters or language-specific collation rules, plain string comparison may not be enough. In those cases, locale-aware collation tools are a better fit than default sorting functions.

That matters when alphabetical order must match user expectations in multilingual applications rather than only code-level ASCII ordering.

Sorting Rules Should Match the Audience

Internal data pipelines may be fine with byte-level or case-sensitive ordering, but user-facing lists often need case-insensitive or locale-aware behavior. Choosing the right PHP sort function is therefore partly a UX decision, not only a syntax decision. Always sort in the way the receiving screen or report actually expects.

Common Pitfalls

• Using sort() on an associative array and losing the original keys.
• Sorting by value when the real requirement was alphabetical key order.
• Ignoring case sensitivity and then being surprised by uppercase letters grouping oddly.
• Using default string comparison for user-facing multilingual text that needs locale-aware ordering.
• Forgetting that arrays of records need a custom comparator instead of basic sort().

Summary

• Use sort() for indexed arrays when keys do not matter.
• Use asort() to sort associative arrays by value while preserving keys.
• Use ksort() when the keys themselves should be alphabetically ordered.
• Use usort() or related custom sorting functions for case-insensitive or record-based sorting.
• Choose the PHP sorting function based on both the array shape and the ordering semantics you actually need.