Exploring the PHP Array Functions: array(), is_array(), in_array(), array_merge(), and array_keys()

• Jul 10, 2023

Arrays are an essential data structure in PHP, and they offer a variety of built-in functions to manipulate and work with array data efficiently. In this article, we will explore some of the commonly used PHP array functions, namely is_array(), in_array(), array_merge(), and array_keys().

1. is_array()

The is_array() function is used to check whether a variable is an array or not. It returns true if the variable is an array and false otherwise. Here's an example:

$fruits = array('apple', 'banana', 'orange');
if (is_array($fruits)) {
   echo "The variable is an array.";
} else {
   echo "The variable is not an array.";
}

In this case, the output will be "The variable is an array" since $fruits is indeed an array.

2. in_array()

 The in_array() function is used to check whether a specific value exists in an array. It takes two parameters: the value to search for and the array to search in. If the value is found, it returns true; otherwise, it returns false. Here's an example:

$fruits = array('apple', 'banana', 'orange');
if (in_array('banana', $fruits)) {
   echo "The array contains 'banana'.";
} else {
   echo "The array does not contain 'banana'.";
}

In this case, the output will be "The array contains 'banana'" since 'banana' is present in the $fruits array.

3. array_merge()

The array_merge() function is used to merge two or more arrays into a single array. It takes multiple arrays as arguments and returns a new array containing all the elements from the input arrays. Here's an example:

$fruits1 = array('apple', 'banana', 'orange');
$fruits2 = array('kiwi', 'grape');
$mergedFruits = array_merge($fruits1, $fruits2);
print_r($mergedFruits);

The output will be:

Array
(
   [0] => apple
   [1] => banana
   [2] => orange
   [3] => kiwi
   [4] => grape
)

In this example, the array_merge() function combines the elements from $fruits1 and $fruits2 arrays into a single array called $mergedFruits.

4. array_keys()

The array_keys() function is used to retrieve all the keys or a subset of keys from an array. It takes the input array as a parameter and returns an array containing all the keys. Here's an example:

$fruits = array('apple' => 'red', 'banana' => 'yellow', 'orange' => 'orange');
$keys = array_keys($fruits);
print_r($keys);

The output will be:

Array
(
   [0] => apple
   [1] => banana
   [2] => orange
)

In this case, the array_keys() function extracts the keys from the $fruits array and stores them in the $keys array.