Clean a string.

clean.php

<?php
/**
 *  Clean a string.
 *
 *  @param   string  $string  The string that needs to be cleaned
 *  @return  string           The string that has been cleaned
 */
function clean( $string, $divider='-', $camelcase=false ) {
    // Remove special characters
    $string = preg_replace('/[^\w]+/', ' ', $string);

    // Remove whitespace
    $string = trim( $string );

    // Make lowercase
    $string = strtolower( $string );

    if( !$camelcase ) {
        // Replace spaces with the divider
        $string = preg_replace('/[^\w]+/', $divider, $string);
    } else {
        // Make all the words uppercase
        $string = ucwords( $string );

        // Remove spaces and special characters
        $string = preg_replace( '/[^A-Za-z0-9]/', '', $string );

        // Lowercase the first word
        $string = lcfirst( $string );
    }

    return $string;
}