Helper Class in PHP

Question

I want create a helper class that containing method like cleanArray, split_char, split_word, etc.

The helper class it self will be used with many class. example :

Class A will user Helper, Class B, Class C, D, E also user Helper Class

what the best way to write and use helper class in PHP ?

what i know is basic knowledge of OOP that in every Class that use Helper class must create a helper object.

$helper = new Helper();

It that right or may be some one can give me best way to do that.

I also will create XXX Class that may use Class A, B, C, etc.

UPDATE : ->FIXED my fault in split_word method :D

Based on Saul, Aram Kocharyan and alex answer, i modified my code, but its dont work, i dont know why.

<?php
class Helper {
    static function split_word($text) {
        $array =  mb_split("\s", preg_replace( "/[^\p{L}|\p{Zs}]/u", " ", $text ));
        return $this->clean_array($array);
    }
    static function split_char($text) {
        return preg_split('/(?<!^)(?!$)/u', mb_strtolower(preg_replace( "/[^\p{L}]/u", "", $text )));
    }
}
?>

and i use in other Class

<?php
include "Helper.php";
class LanguageDetection {
    public function detectLanguage($text) {
        $arrayOfChar = Helper::split_char($text);
        $words = Helper::split_word($text);
        return $arrayOfChar;
    }
}
$i = new Detection();
print_r($i->detectLanguage("ab  cd    UEEef   する ح      خهعغ فق  12  34   ٢ ٣  .,}{ + _"));
?>

Answer 1

Helper classes are usually a sign of lack of knowledge about the Model's problem domain and considered an AntiPattern (or at least a Code Smell) by many. Move methods where they belong, e.g. on the objects on which properties they operate on, instead of collecting remotely related functions in static classes. Use Inheritance for classes that share the same behavior. Use Composition when objects are behaviorally different but need to share some functionality. Or use Traits.

The static Utils class you will often find in PHP is a code smell. People will throw more or less random functions into a class for organizing them. This is fine when you want to do procedural coding with PHP<5.2. As of 5.3 you would group those into a namespace instead. When you want to do OOP, you want to avoid static methods. You want your objects to have High Cohesion and Low Coupling. Static methods achieve the exact opposite. This will also make your code less testable.

• Are Helper Classes Evil?
• Killing the Helper class, part two
• Functional Decomposition AntiPattern
• Is the word "Helper" in a class name a code smell?

Moreover, every Class that use Helper class must create a helper object is a code smell. Your collaborators should not create other collaborators. Move creation of complex object graphs into Factories or Builders instead.