php - Using object property as default for method property


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I'm trying to do this (which produces an unexpected T_VARIABLE error):

public function createShipment($startZip, $endZip, $weight = 
$this->getDefaultWeight()){}

I don't want to put a magic number in there for weight since the object I am using has a "defaultWeight" parameter that all new shipments get if you don't specify a weight. I can't put the defaultWeight in the shipment itself, because it changes from shipment group to shipment group. Is there a better way to do it than the following?

public function createShipment($startZip, $endZip, weight = 0){
    if($weight <= 0){
        $weight = $this->getDefaultWeight();
    }
}

Всички отговори
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    This isn't much better:

    public function createShipment($startZip, $endZip, $weight=null){
        $weight = !$weight ? $this->getDefaultWeight() : $weight;
    }
    
    // or...
    
    public function createShipment($startZip, $endZip, $weight=null){
        if ( !$weight )
            $weight = $this->getDefaultWeight();
    }
    

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    Neat trick with boolean OR operator:

    public function createShipment($startZip, $endZip, $weight = 0){
        $weight or $weight = $this->getDefaultWeight();
        ...
    }
    

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    This will allow you to pass a weight of 0 and still work properly. Notice the === operator, this checks to see if weight matches "null" in both value and type (as opposed to ==, which is just value, so 0 == null == false).

    PHP:

    public function createShipment($startZip, $endZip, $weight=null){
        if ($weight === null)
            $weight = $this->getDefaultWeight();
    }
    

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    You can use a static class member to hold the default:

    class Shipment
    {
        public static $DefaultWeight = '0';
        public function createShipment($startZip,$endZip,$weight=Shipment::DefaultWeight) {
            // your function
        }
    }
    

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    Improving upon Kevin's answer if you are using PHP 7 you may do:

    public function createShipment($startZip, $endZip, $weight=null){
        $weight = $weight ?: $this->getDefaultWeight();
    }