PHP array_search Function

last modified March 13, 2025

The PHP array_search function searches an array for a given value. It returns the first corresponding key if the value is found. This is useful for locating elements in arrays.

Basic Definition

The array_search function searches for a value in an array. It returns the key of the found element or false if not found. The search is case-sensitive for strings.

Syntax: array_search(mixed $needle, array $haystack, bool $strict = false): mixed. The strict parameter enables type comparison. Returns false on failure.

Basic array_search Example

This demonstrates searching for a value in a simple indexed array.

basic_array_search.php

<?php

$fruits = ["apple", "banana", "cherry", "date"];
$key = array_search("cherry", $fruits);

if ($key !== false) {
    echo "Found at index: $key"; 
} else {
    echo "Not found";
}

This searches for "cherry" in the fruits array. The function returns 2, the index of "cherry". Note the strict (!==) comparison to distinguish from 0.

Associative Array Search

Searching in an associative array returns the corresponding key.

assoc_array_search.php

<?php

$user = [
    "name" => "John",
    "age" => 30,
    "email" => "john@example.com"
];

$key = array_search("john@example.com", $user);

if ($key !== false) {
    echo "Email field: $key"; 
} else {
    echo "Not found";
}

This finds the email value in an associative array. The function returns "email", the key where the value was found. Works with any array type.

Strict Type Comparison

Using strict mode ensures both value and type match during search.

strict_search.php

<?php

$values = ["10", 10, 20, 30];
$key = array_search(10, $values, true);

if ($key !== false) {
    echo "Found at index: $key"; 
} else {
    echo "Not found";
}

With strict mode on, the string "10" doesn't match integer 10. The function returns 1, where the integer 10 is located. Type matters in strict mode.

Searching for False Values

Special care is needed when searching for false, 0, or empty strings.

false_search.php

<?php

$data = [true, false, 0, ""];
$key = array_search(false, $data);

if ($key !== false) {
    echo "Found at index: $key"; 
} else {
    echo "Not found";
}

This finds the false value at index 1. Always use strict comparison (!==) to distinguish between found at index 0 and not found (false) cases.

Searching in Multidimensional Arrays

For multidimensional arrays, combine array_search with array_column.

multi_array_search.php

<?php

$users = [
    ["id" => 1, "name" => "Alice"],
    ["id" => 2, "name" => "Bob"],
    ["id" => 3, "name" => "Charlie"]
];

$key = array_search("Bob", array_column($users, "name"));

if ($key !== false) {
    echo "Found at index: $key"; 
} else {
    echo "Not found";
}

This searches for "Bob" in the name column of a 2D array. array_column extracts the name values, then array_search finds the index. Useful for database-like data.

Best Practices

Strict Comparison: Always use !== to check return values.
Type Safety: Use strict mode when types matter.
Performance: For large arrays, consider alternative data structures.
Readability: Document searches when logic isn't obvious.
Error Handling: Handle false returns appropriately.

Source

PHP array_search Documentation

This tutorial covered the PHP array_search function with practical examples showing its usage for various array searching scenarios.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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