在foreach循环之前需要存储explode（）的结果吗？

Question

Is it necessary to store the result of explode() if all it will be used for is a loop?

$lines = explode(PHP_EOL, $data);
foreach ($lines as $line) {
    // do stuff
}

Is there any reason not to call it directly within the loop? Will explode() be called once, or for every iteration?

foreach (explode(PHP_EOL, $data) as $line) {
    // do stuff
}

Answer 1

explode() will only be called once inside your foreach loop, if you have a very big code, you will have two choices:

1. Optimization/Speed:

Each variable holds some bytes of the memory, so if you have a big web application, i suggest calling the explode() inside the foreach, but if your application isn't that big, i don't think it will hurt to allocate some bytes.

2. Cleaner code:

The second option, is a clean code, if you assign your explode to a variable, it will be useful for later uses, and it will also make it easier to debug.

I'd like also to recommend this article for more informations.