PHP - Start Case Function

str_start_case.php

<?php

if(!function_exists('str_start_case'))
{
    /**
     * @param $str       string Required.
     * @param $replace   array  Optional. Default an empty array.
     * @param $separator string Optional. Default space.
     */
    function str_start_case(string $str, array $replace=[], string $separator=" ")
    {
        $str = preg_split("/(?=[A-Z])|([\s\_\-])/", ucfirst($str), -1, PREG_SPLIT_NO_EMPTY);
        $str = array_map(function($str) use($replace) {
            if(!empty($replace)) $str = str_replace(array_keys($replace), array_values($replace), $str);
            return strtoupper($str[0]) . substr($str, 1);
        }, $str);

        return implode($separator, $str);
    }
}

Usage:

<?php

$message = "welcome_to_the_jungle";

echo str_start_case($message);

Output:

Welcome To The Jungle