How to get specific key value from array in PHP ?
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 1:
<?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
$arr = [1, 2, 3];
// Check the key existence with
// the built-in 'isset' function
if (isset($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
$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.