How to get specific key value from array in PHP ?

Last Updated : 04 Jul, 2024

In this article, we will see how to get specific key values from the given array. PHP array is a collection of items that are stored under keys. There are two possible types of keys: strings and integers. For any type of key, there is a common syntax to get a specific value by key — square brackets.

Example:

PHP

<?php

$mixedArr = [
    10,
    20,
    'hello' => 'world',
    30,
];

// Get a specific value by index
$firstItem = $mixedArr[0];
echo "An item by index 0: {$firstItem}\n";

// Get a specific value by string key
$stringItem = $mixedArr['hello'];
echo "An item by key 'hello': {$stringItem}\n";

?>

Output

An item by index 0: 10
An item by key 'hello': world

Example 2: Sometimes we can accidentally try to get a non-existent item from the array. In this case, PHP throws a NOTICE. To avoid the issue, we have to check the key existence before accessing it.

PHP

<?php

$arr = [1, 2, 3];

// Check the key existence with 
// the built-in 'isset' function
if (isset($arr[10])) {
    echo "index 10 value is: {$arr[10]}\n";
} else {
    echo "There are no value under the index 10\n";
}

$value = $arr[10] ?? 'unknown';

echo "A value under the index 10: {$value}\n";

?>

Output

There are no value under the index 10
A value under the index 10: unknown

Example 3: Using array_key_exists Function

The array_key_exists function is another way to check if a specific key exists in an array. This function checks if the given key or index exists in the array. Unlike isset, array_key_exists will return true even if the value associated with the key is null.

PHP

<?php
$arr = ['a' => null, 'b' => 2];
// Nikunj Sonigara 
// Check the key existence with
// the built-in 'array_key_exists' function
if (array_key_exists('a', $arr)) {
    echo "The key 'a' exists in the array.\n";
} else {
    echo "The key 'a' does not exist in the array.\n";
}

if (array_key_exists('c', $arr)) {
    echo "The key 'c' exists in the array.\n";
} else {
    echo "The key 'c' does not exist in the array.\n";
}
?>

Output

The key 'a' exists in the array.
The key 'c' does not exist in the array.

Using isset()

In PHP, isset() checks if a variable is set and not null. To get a specific key's value from an array, use isset() to ensure the key exists before accessing its value, avoiding errors if the key is missing.

Example:

PHP

<?php
$array = ["name" => "John", "age" => 25, "country" => "USA"];
$key = "age";

if (isset($array[$key])) {
    echo $array[$key]; // Output: 25
} else {
    echo "Key is not set";
}
?>

Output

Using array_key_first and array_key_last Functions

The array_key_first function returns the first key of the given array without affecting the internal array pointer, while the array_key_last function returns the last key of the given array.

Example: