Array Functions

Add, remove and inspect array items with built-in functions.

Syntaxarray_push($array, $value);

PHP provides many functions for working with arrays:

count() — number of elements.
array_push() / array_pop() — add / remove from the end.
in_array() — check if a value exists.
array_keys() / array_values() — get keys or values.
array_merge() — combine arrays.

Example

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When to use it

Use array_map() to convert an array of prices from dollars to cents before saving to the database.
Filter a list of users with array_filter() to extract only those with an active subscription.
Merge two configuration arrays with array_merge() where the second overrides the first.

More examples

array_map transforms values

array_map() applies a callback to every element and returns a new array, leaving the original unchanged.

<?php
$prices = [9.99, 24.99, 4.49];
$cents  = array_map(fn($p) => (int) round($p * 100), $prices);

print_r($cents); // [999, 2499, 449]

array_filter removes elements

array_filter() keeps elements for which the callback returns true; array_values() re-indexes the result.

<?php
$users = [
    ['name' => 'Alice', 'active' => true],
    ['name' => 'Bob',   'active' => false],
    ['name' => 'Carol', 'active' => true],
];

$active = array_values(
    array_filter($users, fn($u) => $u['active'])
);

echo count($active); // 2

array_merge and array_unique

array_merge() combines arrays with later values winning on duplicate string keys; array_unique() deduplicates values.

<?php
$defaults = ['debug' => false, 'cache' => true,  'timeout' => 30];
$custom   = ['debug' => true,  'timeout' => 60];

$config = array_merge($defaults, $custom);
// debug => true, cache => true, timeout => 60

$tags   = array_unique(['php', 'web', 'php', 'backend']);
print_r($tags); // php, web, backend

Discussion

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