PHP - get all keys from a array that start with a certain string

Question

I have an array that looks like this:

array(
  \'abc\' => 0,
  \'foo-bcd\' => 1,
  \'foo-def\' => 1,
  \'foo-xyz\' => 0,
  // ...
)

Answer 1

In addition to @Suresh Velusamy's answer above (which needs at least PHP 5.6.0) you can use the following if you are on a prior version of PHP:

 0,
    'foo-bcd' => 1,
    'foo-def' => 1,
    'foo-xyz' => 0,
);

$filtered = array_filter(array_keys($input), function($key) {
    return strpos($key, 'foo-') === 0;
});

print_r($filtered);

/* Output:
Array
(
    [1] => foo-bcd
    [2] => foo-def
    [3] => foo-xyz
)
// the numerical array keys are the position in the original array!
*/

// if you want your array newly numbered just add:
$filtered = array_values($filtered);

print_r($filtered);

/* Output:
Array
(
    [0] => foo-bcd
    [1] => foo-def
    [2] => foo-xyz
)
*/