If you want to get user id by login name in WordPress? You can achieve this by using
get_userdatabylogin() function. Use following code in your theme’s functions.php file OR in site specific plugin.
$user = get_userdatabylogin('loginname');
$user = get_userdatabylogin('admin');
if($user) echo $user->ID; // Outputs 1
If you like this question & answer and want to contribute, then write your question & answer and email to freewebmentor[@]gmail.com. Your question and answer will appear on FreeWebMentor.com and help other developers.