Remove keys with false values from array in PHP

I have an associative array with a whole pile of true/false values.

I am trying to remove all keys where the 开发者_JS百科values are false.

So if the array is

array(
  'key1' => true,
  'key2' => false,
  'key3' => false,
  'key4' => true
);

I want to end up with

array(
  'key1' => true,
  'key4' => true
);

How would I do this?

---

$array = array_filter(array(
    'key1' => true,
    'key2' => false,
    'key3' => false,
    'key4' => true
));

array_filter()

---

see http://www.php.net/manual/en/function.unset.php , combine this with a foreach and you have what you need.

also, see http://www.php.net/manual/en/function.array-filter.php

---

for (x=0; x < array.count; x++)
{
     if (key.value == false)
     {
          unset($arr[x]);
     }
}

Just psuedocode, so I hope you know what I mean.

---

Arraydecleration (using PHP 5.4 array shorthand):

$arr = ['key1' => TRUE, 'key2' => FALSE, 'key3' => FALSE, 'key4' => TRUE];

Then remove all keys and values from array where value == FALSE (optionally use strict comparison "==="):

foreach ($arr as $key => $value)
    if ($value == FALSE)
        unset($arr[$key]);

Print results:

print_r($arr);

This last line prints "Array ( [key1] => 1 [key4] => 1 )".