PHP - check if one or more array field exist

Question

Hi

I have a array like this:

array('prefix1_field' => 34,
      'prefix1_anotherfield' => 345,
      'prefix1_andanotherfield' => 565,

      'anotherprefix_field' => 34,
      'anotherprefix_anotherfield' => 345,
      'anotherprefix_andanotherfield' => 565,

      'prefix3_anotherprefix_field' => 34, // <- 'anotherprefix' here should be ignored
      'prefix3_anotherfield' => 345,
      'prefix3_andanotherfield' => 565,
      ...
);

How can I make a function that checks if there are any fields in this array that start with prefix1_ for example?

Answer 1

function check_array_key_prefix_exists($array, $key_prefix) {
  $keys = array_keys($array);
  foreach ($keys as $key) {
    if (0 == substr_compare($key, $key_prefix, 0, strlen($key_prefix))) {
      return true;
    }
  }

  return false;
}

Answer 2

Something like:

function check($arr,$prefix) {
        foreach($arr as $key => $value) {
                if(strcmp(substr($key,0,strlen($prefix)),$prefix)==0) {
                        return true;
                }
        }
        return false;
}

Answer 3

Why not use regular expressions?

function array_has_key_prefix( $array, $key_prefix ) {
  foreach($arr as $key => $value) {
    if( preg_match( "/^" . $key_prefix . "/", $key ) )
      return true;
  }
  return false;
}

Answer 4

Checks if a value exists in multidimensional array

Answer 5

I'd prefer to restructure the array as follows:

$data=array('prefix1'=>array(
                  'field'=>34,
                  'anotherfield'=>345,
               ),
            'prefix2'=>array(
                  'field'=>56,
               ),

...etc.

With that structure, you can just make a quick call to the standard PHP function array_key_exists().

With the structure you have, you'd have to basically roll your own alternative to array_key_exists(), which would involve a foreach() loop and explode() to break the key into bits.

Answer 6

I won't give much as informatio and I'll expilicitly write s.t. similar to the post of Dominique Roger.

function check_array_key_prefix_exists($array, $key_prefix) {
  $keys = array_keys($array);
  foreach ($keys as $key) {
    if (preg_match("#^$key_prefix", $array) {
      return true;
    }
  }

  return false;
}

I don't know if I've answerd your Question part because I didn't run it into he bwowser. Good Luck