More about $this on php -

More about $this on php -

*update example

have read articles , php.net . still having problem understand $this on 'this' example. understand basic used .

let's assume , have function @ end homecoming $this; //nothing come after $this

what $this (at end of method to) refer ? how check/echo-ing $this is

public function check($source, $items = array()){ foreach ($items $item => $rules) { foreach($rules $rule => $rule_value){ $value = trim($source[$item]); $item = escape($item); if($rule === 'required' && empty($value)) { $this->adderror("{$item} required"); } else if(!empty($value)) { switch($rule) { case 'min': if(strlen($value) < $rule_value ) { $this->adderror("{$item} must minimum of {$rule_value} characters"); } break; case 'max': if(strlen($value) > $rule_value ) { $this->adderror("{$item} must maximum of {$rule_value} characters"); } break; } } } } if(empty($this->_errors)) { $this->_passed= true; } homecoming $this; }

*this code part of register , validation class. point still $this @ end refering . thanks

in example, $this refers main class , object.

class mainclass { public function dosomething($x, $y) { $this->content = "rssult is: " . $x+$y; homecoming $this; } public function printme() { echo $this->content; }

}

it returns object , class.

now usage? 1 of fundamental usages method-chaining. well, mean?

have ever seen this?

$myclass = new mainclass(); $myclass->dosomething()->print();

the above code implemented approach called method-chaining, since there chain of methods (functions) called repeatedly without stop.

basically, without method-chaining, above code have been:

$myclass = new mainclass(); $s = $myclass->dosomething(5, 8); $myclass->print();

but method chaining, since each method returns whole class if have had new mainclass() , allows immediate phone call method.

though not new mainclass() since "new" operator creates instance of class, while $this returns current instanced.

in nutshell, $this says php please homecoming current instanced re-create of class (whose properties might have been changed methods called prior returning $this).

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