How does foreach work in php

It should be mentioned, that short list syntax is already implemented since 7. Lots of people think the answer is two because it uses "reference to value, which it doesn't have to copy each value when it loops". Well, that's totally wrong! The array itself wasn't passed by reference to the function, so PHP knows that it isn't allowed to modify the outside array, so it therefore makes a copy of the array's internal iteration offset state that's just a simple number which says which item you are currently at during things like foreach , which costs almost no performance or memory at all since it's just a small number.

That's what MANY people think. But the answer is NO. It re-uses the existing value in memory. With zero performance cost. Alright, so what's the second version doing?

The beloved "iterate values by reference"? The array itself wasn't passed by reference to the function, so PHP knows that it isn't allowed to modify the outside array. If we just give them references to the original array's values, and they assign some new value to their reference, they would destroy the original array which they aren't allowed to touch!

It's almost always BAD! With worse performance, and risks of bugs and quirks as is demonstrated in the manual. Enjoy and good luck with your code! Other tutorials How to check if a list is empty in python? Looking for Freelance Jobs?

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