Why iterating over ArrayIterator ending with endless loop?

Question

Array in my code is quite big so I pasting it in pastebin. http://pastebin.com/6tviT2Xj

I don't understand why I am getting endless loop

Logic of this script is:

$it = new ArrayIterator($options);
while($it->valid()) {
    print $it->key();
    print $it->current();
}

Not using `foreach` when using iterators seems so like PHP3... ;) — Sven, Oct 03 '12 at 13:35
You should use foreach. Better performance than while. Less error prone, like you demonstrated. — Sven, Oct 03 '12 at 13:43
@Sven - Do you have any benchmarks for the better performance you claim? — nickb, Oct 03 '12 at 13:53
@Sven you can't get next Array element using foreach (probably) and I don't care about performance. It just must work — Codium, Oct 03 '12 at 13:55
http://www.phpbench.com/ claims foreach is 5 times faster than while when reading a native array. But I do not believe benchmarks of others, so do your own. :) — Sven, Oct 03 '12 at 14:00

Björn · Accepted Answer · 2012-10-03T13:42:44.753

7

Because you never move in you iterator (with ArrayIterator::next()).

while ($it->valid()) {
    ...
    $it->next();
}

edited Oct 03 '12 at 13:42

answered Oct 03 '12 at 13:31

Björn

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Just Curios .. did you test this code ??? .. You would know it has errors if you did – Baba Oct 03 '12 at 13:38
@Baba - No, I just added the `$it->next()` -- because that's the cause of the problem. What errors do you mean? – Björn Oct 03 '12 at 13:40
Just edited your code with proper formatting .. you can see the diffence – Baba Oct 03 '12 at 13:41

score 3 · Answer 2 · answered Oct 03 '12 at 13:32

3

you should use $it->next(); else you will cicle over the same key eternally

answered Oct 03 '12 at 13:32

kawashita86

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score 2 · Answer 3 · answered Oct 03 '12 at 13:33

2

you're iterating over current element, you need to do $it->next(); to point/go to the next element

answered Oct 03 '12 at 13:33

Teena Thomas

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Baba · Answer 4 · 2012-10-03T13:50:13.227

The main issue is not using $it->next(); in your but that still many not give you the desired output because If you run print $it->current(); it would only return Array since you can not output array information with print.

You should be using RecursiveArrayIterator and RecursiveIteratorIterator since you are dealing with multidimensional array

To get all values try :

$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($options));
foreach ( $it as $key => $val ) {
    echo $key . ":" . $val . "\n";
}

See full demo : http://codepad.viper-7.com/UqF18q

Why iterating over ArrayIterator ending with endless loop?

4 Answers4