Deleting an array element within foreach loop

Question

I have a simple array which contains name of all the countries and total number of users registered on my website from that each country. It's something like this:

Array (
    [1] => Array ( [name] => Afghanistan [total] => 3 )
    [2] => Array ( [name] => Albania [total] => 0 )
)

And, I'm trying to delete array elements (countries) which have 0 users.

I've tried with this code and it's not working:

foreach($country as $row) {
    if ($row['total'] == 0) {
        unset($row);
    }
}

What is wrong with this code?

possible duplicate of How do you remove an array element in a foreach loop? — 7hi4g0
– 7hi4g0, Commented Jan 29, 2014 at 6:47

NikiC · Accepted Answer · 2012-01-20 14:31:08Z

26

If you unset($row) you are only removing the local variable.

Instead fetch the key and remove that:

foreach ($country as $i => $row) {
    if ($row['total'] == 0) {
        unset($country[$i]);
    }
}

answered Jan 20, 2012 at 14:31

NikiC

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1 Comment

user2742371 Over a year ago

But what if you add an & sign before $row (Pass by reference) ?

hakre · Accepted Answer · 2012-01-28 19:45:08Z

3

Foreach creates copies of the keys/values on the array you're looping over, so all you're doing is unsetting the local copy, not the original that's actually in the array. Either access the array directly

foreach($country as $key => $row) {
  if ($row['total'] == 0) {
     unset($country[$key]);
  }
}

or use a reference, unset it and filter NULL elements afterwards:

foreach($country as &$row) {
    if ($row['total'] == 0) {
        $row = (unset) $row;
    }
}
unset($row);
$country = array_filter($country);

edited Jan 28, 2012 at 19:45

hakre

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answered Jan 20, 2012 at 14:32

Marc B

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2 Comments

NikiC Over a year ago

Reference won't work btw. It will still only be a local variable. ;)

hakre Over a year ago

Additionally it's good practise to put the unset($val) after the foreach loop to remove the reference (this would spare the last paragraph of the answer as well).

CompanyDroneFromSector7G · Accepted Answer · 2012-01-20 14:34:51Z

0

Because $row is the value, not the entire element.

Try: foreach ($country as $key => $value) { if ($row['total'] == 0) { unset($country[$key]); } }

answered Jan 20, 2012 at 14:34

CompanyDroneFromSector7G

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