Overwriting Array Elements in PHP

You can also read the current value of an element, perform some operations with it, and write the changed value back into this element:

<?php
	$arr = ['a', 'b', 'c'];
	
	$arr[0] = $arr[0] . '!';
	$arr[1] = $arr[1] . '!';
	$arr[2] = $arr[2] . '!';
	
	var_dump($arr); // will output ['a!', 'b!', 'c!']
?>

The previous code can be rewritten using the .= operator:

<?php
	$arr = ['a', 'b', 'c'];
	
	$arr[0] .= '!';
	$arr[1] .= '!';
	$arr[2] .= '!';
	
	var_dump($arr); // will output ['a!', 'b!', 'c!']
?>

Given the following array:

<?php
	$arr = ['a' => 1, 'b' => 2, 'c' => 3];
?>

Add the number 3 to each element of the array. Display the modified array on the screen.