PHP array_fill_keys Function | Fill Array Specifying Keys

The array_fill_keys is an inbuilt Function in PHP. It fills an array with values, also specifying the keys. Also, it works similarly to the PHP array_fill Function. In this article, we will discuss the PHP array_fill_keys Function. Also, we will discuss a few examples of using it.

Syntax

array array_fill_keys ( $keys, $value )

Parameters

The PHP array_fill_keys Function expects two mandatory parameters. The description of the parameters is as follows:

• $keys: The first parameter is a mandatory array consisting of keys that will be used in creating the new array.
• $value: The second parameter is the mandatory value. If this parameter is a single value, then the new array contains this value in all the keys defined before. However, if this value is an array, then all the keys contain this array as values.

Return Value

The PHP array_fill_keys Function returns an array containing the key-value pair according to the parameters.

Examples

Let’s discuss a few examples of using the array_fill_keys function.

Example 1: Single Value Input

For instance, consider a single value input to the function.

<?php
	
	$keys = array('apple', 5, '10', 'mango');
	$value = 'fruits';
	$array = array_fill_keys($keys, $value);
	print_r($array);
	/*
	Array
	(
	    [apple] => fruits
	    [5] => fruits
	    [10] => fruits
	    [mango] => fruits
	)
	*/
?>

In the above example, the $keys array contain mixed values (both string and keys). The final array has the $value to all the keys in the new array.

Example 2: Array as $value

You can also pass an array in the $value parameter.

<?php
	
	$keys = array('apple', 5, '10');
	$value = array('vegetables', 'fruits');
	$array = array_fill_keys($keys, $value);
	print_r($array);
	/*
	Array
	(
	    [apple] => Array
	        (
	            [0] => vegetables
	            [1] => fruits
	        )
	    [5] => Array
	        (
	            [0] => vegetables
	            [1] => fruits
	        )
	    [10] => Array
	        (
	            [0] => vegetables
	            [1] => fruits
	        )
	)
	*/
?>

As you can observe, the new array consists of the value array to all the keys as in the $keys array.

Expert Tip

The function can also be implemented using PHP array_combine and array_fill Function. This is demonstrated below:

<?php
	
	$keys = array('apple', 5, '10');
	$value = 'fruits';
	$array = array_combine($keys,array_fill(0,count($keys),$value));
	print_r($array);
	/*
	Array
	(
	    [apple] => fruits
	    [5] => fruits
	    [10] => fruits
	)
	*/
?>

Conclusion

In conclusion, we discussed the PHP array_fill_keys Function. Also, you can read more about it on the Official Documentation. You can also read about array_fill Function which is similar to this function. You might also be interested in other PHP Array Functions.