How to split a string into individual characters using PHP?

In one of our php project, we had to split a string into individual characters. I thought there should be some built-in function for doing this. But I couldn’t find the appropriate build-in php function.

Currently we are using below code snippet for doing this split..

for($i=0;$i< strlen($inputstring);$i++){
 $letterarray[]=$inputstring[$i];
 }

You can let me know thro’ the comments if you know any suitable function for doing this task.