if i filter an array with array_filter to eliminate null values, keys are preserved and this generated "holes" in the array. Eg:
The filtered version of
[0] => 'foo'
[1] => null
[2] => 'bar'
is
[0] => 'foo'
[2] => 'bar'
How can i get, instead
[0] => 'foo'
[1] => 'bar'
?
Using this input:
$array=['foo',NULL,'bar',0,false,null,'0',''];
There are a few ways you could do it. Demo
It's slightly off-topic to bring up array_filter's greedy default behavior, but if you are googling to this page, this is probably important information relevant to your project/task:
var_export(array_values(array_filter($array))); // NOT GOOD!!!!!
Bad Output:
array (
0 => 'foo',
1 => 'bar',
)
Now for the ways that will work:
Method #1: (array_values(), array_filter() w/ !is_null())
var_export(array_values(array_filter($array,function($v){return !is_null($v);}))); // good
Method #2: (foreach(), auto-indexed array, !==null)
foreach($array as $v){
if($v!==null){$result[]=$v;}
}
var_export($result); // good
Method #3: (array_walk(), auto-index array, !is_null())
array_walk($array,function($v)use(&$filtered){if(!is_null($v)){$filtered[]=$v;}});
var_export($filtered); // good
All three methods provide the following "null-free" output:
array (
0 => 'foo',
1 => 'bar',
2 => 0,
3 => false,
4 => '0',
5 => '',
)
From PHP7.4, you can even perform a "repack" like this: (the splat operator requires numeric keys)
Code: (Demo)
$array = ['foo', NULL, 'bar', 0, false, null, '0', ''];
$array = [...array_filter($array)];
var_export($array);
Output:
array (
0 => 'foo',
1 => 'bar',
)
... but as it turns out, "repacking" with the splat operator is far less efficient than calling array_values().
