PHP while (list($key, ) = each($array)) vs. while (list($key) = each($array))

Question

I have been going through the entire documentation and stackoverflow Q&A and couldn't find any answer for this. In php, are these two while the exact same or are there differences between them. And if so, which?

while (list($key, ) = each($array))

and

while (list($key) = each($array))

I know I can convert the first to

foreach (array_keys($array) as $key)

But can I do the same conversion to while (list($key) = each($array))?

The each() function is deprecated and will be removed in a future PHP version. — rickdenhaan
– rickdenhaan, Commented Jul 14, 2018 at 11:24
Having said that, a quick test script seems to indicate that the second while-loop does exactly the same thing as the first, so you could use the same solution. — rickdenhaan
– rickdenhaan, Commented Jul 14, 2018 at 11:28
Thanks, @rickdenhaan. The reason I am asking is exactly because each is deprecated and I am adapting the script to php 7.2, and thus don't want to make any mistakes while adapting the code to use foreach. — Nikita 웃
– Nikita 웃, Commented Jul 14, 2018 at 11:32
@rickdenhaan, off-topic, but isn't it odd that your script take 14ms on php 5.6.30 and 23ms (almost double time) on php 7.2.7? — Nikita 웃
– Nikita 웃, Commented Jul 14, 2018 at 11:44
Not particularly. The array in that test script only contains 5 items, with that small a sample the script's runtime is heavily influenced by other system resource usage. I just tried running the same script with an array that has 100.000 items in it, that took 313 ms on PHP 5.6 and 110 ms on PHP 7.2. — rickdenhaan
– rickdenhaan, Commented Jul 14, 2018 at 11:55

Nikita 웃 · Accepted Answer · 2018-07-29 05:23:23Z

4

Thanks to @rickdenhaan for his test script that shows they are identical, I wanted to point out that there is 1 more way to convert while (list($key, ) = each($array)):

foreach ($array as $key => $value)

Examples: https://3v4l.org/NV8MD

answered Jul 29, 2018 at 5:23

Nikita 웃

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