i have this code
$courses = array("name_lic", "name_mes", "name_dou"); How i can add to array if name_lic, name_mes, name_doucare defined?
For example: name_lic is defined then, is insert in array, name_mes is not defined or is empty then is not inserted in the array and name_dou also.
basically the array only can have strings that are defined
in my example should be:
$courses = array("name_lic"); I'm going to guess that "inserted by user" means a value present in $_POST due to a form submission.
If so, then try something like this
$courses = array("name_lic", "name_mes", "name_dou"); // Note, changed your initial comma separated string to an actual array $selectedCourses = array(); foreach ($courses as $course) { if (!empty($_POST[$course])) { $selectedCourses[] = $course; } } 
!empty() does more than merely checking if a variable is defined.Do you mean something like
if (isset($name_lic)) { $courses[] = $name_lic; } ... etc for name_mes, name_dou
isset will return TRUE if the value is an empty string, which apparently you don't want. Try
if (!empty($_POST['name_lic'])){ $courses[] = $_POST['name_lic']; } // etc For example, if you want to do this for all values of $_POST:
foreach ($_POST as $key => $value){ if (!empty($value)){ $courses[$key] = $value; } } First of all, if your code is:
$courses = array("name_lic, name_mes, name_dou"); then $courses is an array with only one key, you should remove the " " like this:
$courses = array("name_lic", "name_mes", "name_dou"); Now if you want to know if the array contains a key with the value "name_lic" you should use the function in_array() like this:
if (in_array("name_lic", $courses)) { //Do stuff } 
$_POSTarray?"