我可以安全地在php foreach语句声明中放置一个函数吗？

Question

Is it safe to put a function in the foreach statement ?

foreach( get_class_methods( $object ) as $entityMethod ) {
    // Do something
}

Does the get_class_methods() function will be called at each loop ? Is there any drawback ?

Answer 1

The function will only get evaluated once, when entering the loop. But you could have tested that yourself by making a function that increments a global variable every time it's called.

As far as drawbacks, none that I can think of..

Answer 2

The only time this would be unsafe is if the function could return something that was not iterable (like null , or a string , etc). That particular function does return null on any error.