How to delete elements in array?

Question

I have an array like this :

array() {
  ["AG12345"]=>
  array() { 

  }
  ["AG12548"]=>
  array() { 

  }
  ["VP123"]=>
  array() { 

  }

I need to keep only arrays with keys which begin with "VP"

It's possible to do it with one function ?

Answer 1

Yes, just use unset():

foreach ($array as $key=>$value)
{
  if(substr($key,0,2)!=="VP")
  {
    unset($array[$key]);
  }
}

Answer 2

From a previous question: How to delete object from array inside foreach loop?

foreach($array as $elementKey => $element) {
    if(strpos($elementKey, "VP") == 0){
        //delete this particular object from the $array
        unset($array[$elementKey]);
    } 
}

Answer 3

This works for me:

$prefix = 'VP';
for ($i=0; $i <= count($arr); $i++) {
   if (strpos($arr[$i], $prefix) !== 0)
      unset($arr[$i]);
}

Answer 4

Another alternative (this would be way simpler if it were values instead):

array_intersect_key($arr, array_flip(preg_grep('~^VP~', array_keys($arr))));

Answer 5

This is only a sample how to do this, you have probably many other ways!

// sample array
$alpha = array("AG12345"=>"AG12345", "VP12548"=>"VP12548");
foreach($alpha as $val) 
{
    $arr2 = str_split($val, 2);
    if ($arr2[0] == "VP")
        $new_array = array($arr2[0]=>"your_values");
}