这个特定的StrPos如何在PHP中工作？

Question

I have the following code. I'm wondering if it's working like I think it is:

//Gift Card Redemption
        if(strpos($_order->getDiscountDescription(), 'Gift Card') !== false){
                $order .= 'RGC1*1*'.$_order->getDiscountDescription().'*****';
                $order .= "\r\n";
        }  

How I think it works: look for 'Gift Card' in $_order->getDiscountDescription() , and if it's not false, do something. I don't follow what that something is, though. Any ideas on that?

Answer 1

This basically checks to see if the string literal ' Gift Card ' is contained in the string returned by $_order->getDiscountDescription() (ie presuming it returns a string...). The use of the operator !== and operand false is used because the position might be 0, meaning the start of the string. Refer to the warning on the documentation for strpos() :

Warning This function may return Boolean FALSE , but may also return a non-Boolean value which evaluates to FALSE . Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

When that condition is true (ie the order description contains 'Gift Card') then the variable $order gets appended with the string literal RGC1*1* followed by the return value from the call to $_order->getDiscountDescription() , 5 asterisk characters, a carriage return character (ie \\r ) and a new line character (ie \\n ).