Thanks for the response but there is one problem.
I failed to say in my first post (sorry) that the name of the players is already in a string.
So I have an array whit the nicks and I want to check if the user I am currently working whit is in the clan |sun|.
So
Code:
nickname[] = |sun|lalala
tag[] = |sun|
if (tag[i] is in nickname[i]) {
//do code
}