forEach skips last element in loop

Question

I'm looping over a countries object. However, when I reference that object I notice that the second to last element is duplicated, while the last element is skipped. Uruguay appears twice, while America does not appear at all.:

foreach($countries as &$country){
    $country->keywords = array_merge(array($country->name),$country->synonyms);
    var_dump($country->key);
}

var_dump('-----------------------------------------');

foreach($countries as $country){
    var_dump($country->key);
}

exit;

And my output. Scroll all the way to the bottom to see uruguay now appears twice:

string(7) "algeria"
string(9) "argentina"
string(9) "australia"
string(7) "belgium"
string(6) "bosnia"
string(8) "cameroon"
string(5) "chile"
string(8) "columbia"
string(9) "costarica"
string(5) "ivory"
string(7) "croatia"
string(8) "ecquador"
string(7) "england"
string(6) "france"
string(7) "germany"
string(5) "ghana"
string(6) "greece"
string(8) "honduras"
string(4) "iran"
string(5) "italy"
string(5) "japan"
string(6) "mexico"
string(11) "netherlands"
string(7) "nigeria"
string(8) "portugal"
string(6) "russia"
string(5) "korea"
string(5) "spain"
string(11) "switzerland"
string(7) "uruguay"
string(7) "america"
string(41) "-----------------------------------------"
string(7) "algeria"
string(9) "argentina"
string(9) "australia"
string(7) "belgium"
string(6) "bosnia"
string(8) "cameroon"
string(5) "chile"
string(8) "columbia"
string(9) "costarica"
string(5) "ivory"
string(7) "croatia"
string(8) "ecquador"
string(7) "england"
string(6) "france"
string(7) "germany"
string(5) "ghana"
string(6) "greece"
string(8) "honduras"
string(4) "iran"
string(5) "italy"
string(5) "japan"
string(6) "mexico"
string(11) "netherlands"
string(7) "nigeria"
string(8) "portugal"
string(6) "russia"
string(5) "korea"
string(5) "spain"
string(11) "switzerland"
string(7) "uruguay"
string(7) "uruguay"

You may want to try to `unset($country)` after the first loop. References have minor gotchas. — Maerlyn, Jun 25 '14 at 18:14
I'm fully aware of how `by reference` works in a foreach loop, look at the names against the comments in your linked article.... explain how reset will help and unset won't? — Mark Baker, Jun 25 '14 at 18:16
@pce reset has no meaning in context with foreach, as it uses it's own array-internal pointer, not the one stored together in the array in the zval. — Maerlyn, Jun 25 '14 at 18:17
@AakilFernandes `unset($country);` after the end of your first `foreach()` loop will __not__ destroy the array, it will fix your problem — Mark Baker, Jun 25 '14 at 19:03
@MarkBaker, I ran `unset` on `countries` instead of `country`, my bad. your answer is correct — A F, Jun 25 '14 at 19:08
@AakilFernandes yeah, i deleted my comments. i already linked to a blog entry about references and foreach and *unset*, but i accidentally thought of another issue :/ — pce, Jun 25 '14 at 21:11

score 2 · Accepted Answer · answered Jun 25 '14 at 19:05

2

foreach($countries as &$country){
    $country->keywords = array_merge(array($country->name),$country->synonyms);
    var_dump($country->key);
}
unset($country);

var_dump('-----------------------------------------');

foreach($countries as $country){
    var_dump($country->key);
}

answered Jun 25 '14 at 19:05

Mark Baker

209,507
32
346
385

It works because you're unsetting a reference, not the actual array entry; otherwise the reference is still pointing to the last entry in your array when you start iterating over that array again, so it overwrites the entry pointed to by that reference – Mark Baker Jun 25 '14 at 19:13
See my answer to [this question](http://stackoverflow.com/questions/4969243/strange-behavior-of-foreach/4969286#4969286) for an explanation – Mark Baker Jun 25 '14 at 19:16

forEach skips last element in loop

1 Answers1