Notes on using PHP functions Notes on using solid state drives Notes on using ID cards etc. Notes on using

Note:

1. PHP function parameters, when using default parameters, any default parameters must be placed to the right of any non-default parameters, otherwise the function will not work as expected.

2. PHP cannot return multiple values, but you can achieve the same effect by returning an array

function getArr(){

Return array(1,2,3);

}

list( $a,$b,$c)=getArr();

3. To return a reference from a function, you must use the operator &

global $arr;

$ both when declaring the function and when assigning the return value to a variable. arr=array(3);

function & return_reference(){

global $arr;

print_r($arr);

return $arr;

}

$newref =& return_reference();

$newref[0]=4;

$newref=& return_reference();

4. Anonymous function

class Cart{

const PRICE_BUTTER=1.00;

const PRICE_MILK=3.00;

const PRICE_EGG=6.95;

protected $products=array();

public function getQuantity($product){

return isset( $this->products[$product])?$this->products[$product]:FALSE;

                                                                     

$total=0.00;

$callback=function($quantity,$product) use ($tax,&$total){

$pricePerItem=constant(__CLASS__."::PRICE_".strtoupper($product));

$total +=($pricePerItem*$quantity)*($tax+1.0);

}

array_walk($this->products,$callback);

return round($total,2);

}}

$mycart=new Cart;

$mycart->add('butter',1);$mycart-> ;add('milk',3);$mycart->add('eggs',6);

echo $mycart->getTotal(0.05);

The above introduces the points to note when using PHP functions, including usage notes and PHP content. I hope it will be helpful to friends who are interested in PHP tutorials.