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 ?

Possible Duplicate http://stackoverflow.com/questions/2304570/how-to-delete-object-from-array-inside-foreach-loop — CLo, Mar 12 '12 at 15:29

score 3 · Accepted Answer · answered Mar 12 '12 at 15:28

3

Yes, just use unset():

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

answered Mar 12 '12 at 15:28

2

+1, but I'd use `substr()` instead of regexp. It is simpler and faster. – Minras Mar 12 '12 at 15:31
why is the "!" in there on line 3? – crunkchitis May 03 '12 at 16:25
@crunkchitis - The condition `substr($key,0,2)!=="VP"` checks to see whether the substring consisting of the first two characters of the string `$key` are identical to the string `"VP"`. In other words, the `!` represents negation. – May 03 '12 at 16:59
1

@JackManey - I'm new to php so I didn't know "!==" existed, I only knew about "!=". Turns out it was important to what I was working on. Identical vs. equal. Thanks. – crunkchitis May 04 '12 at 17:28

score 1 · Answer 2 · edited May 23 '17 at 12:11

1

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]);
    } 
}

edited May 23 '17 at 12:11

Community

1
1

answered Mar 12 '12 at 15:30

CLo

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score 0 · Answer 3 · answered Mar 12 '12 at 15:44

0

This works for me:

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

answered Mar 12 '12 at 15:44

anubhava

761,203
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That's fair you are OP after all :) but to me substr function will also need another function call i.e. strlen to get the length of the prefix. – anubhava Mar 12 '12 at 15:48

score 0 · Answer 4 · answered Mar 12 '12 at 15:57

0

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

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

answered Mar 12 '12 at 15:57

Alix Axel

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devasia2112 · Answer 5 · 2012-03-12T16:11:29.897

-1

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");
}

edited Mar 12 '12 at 16:11

answered Mar 12 '12 at 16:06

devasia2112

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How to delete elements in array?

5 Answers5