PHP/Data Structure/array keys

array_keys() function returns an array containing all keys

   <source lang="html4strict">

//If the search_element is included, then only the keys matching that particular element are returned; otherwise, all keys constituting the array are returned. //Its syntax is: array array_keys (array array, mixed [search_element]) //use array_keys() to return the key of a given element: <? $wines = array ("A" => "a","Q" => "q","E" => "e"); $labels = array_keys($wines); print $labels; print "
"; $labels = array_keys($wines, "a"); print_r $labels; ?>

 </source>
   
  

array_keys( ) returns an array of all the keys in that array

   <source lang="html4strict">

array array_keys ( array arr [, mixed search [, bool strict]] ) <?

   $users[923] = "T";
   $users[100] = "S";
   $users[1202] = "C";
   $userids = array_keys($users);

   $users[923] = "T";
   $users[100] = "S";
   $users[1202] = "C";
   $userids = array_keys($users, "T");

?>

 </source>
   
  

Outputting Using array_values() and array_keys() for Backward Compatibility

   <source lang="html4strict">

<?

   $countries_languages = array("Germany" => "German", "France" => "French", "Spain" => "Spanish"); 
   

printf("

Languages: %s.

\n",

   implode(", ", array_values($countries_languages)) ); 
   

printf("

Countries: %s.

\n",

   implode(", ", array_keys($countries_languages)) ); 
   

?>

 </source>
   
  

Return all the keys of an array with array array_keys (array input [, mixed search_value])

   <source lang="html4strict">

<? $array = array(0 => 100, "color" => "red"); array_keys ($array); $array = array(1, 100, 2, 100); array_keys ($array, 100); ?>

 </source>