Replace uppercase character with dot in php

Question

I have a string that looks like this:

$string = 'helloWorldAndStackOverflow';

I want it to end with:

$string = 'hello.world.and.stack.overflow';

So where I have a uppercase character it should prepend a . character. Then I can use strtolower on the whole thing.

How can I prepend the dot?

Answer 1

You can use preg_replace to identify the uppercase and replace that.

$string = 'helloWorldAndStackOverflow';
$string = preg_replace('/([A-Z])/', '.$1', $string);

After that you can simply use strtolower

$string = strtolower($string);

to convert that into lower case.

Answer 2

you can use preg_replace_callback for replace. try below code,

<?php
$string = 'helloWorldAndStackOverflow';
$dottedString = preg_replace_callback('/[A-Z]/', function($matches){
    return $matches[0] = '.' . ucfirst($matches[0]);
}, $string);
echo $dottedString;
?>