如何检查一个数组中的元素是否在另一个数组中?

I have two arrays one is fix to be 8 letters and the other depends on the user. I have to take user input and put in an array (done) but I need to check if the users input (it is a word) letters are in the other array ? how can I do it ?I have two arrays one is fix to be 8 letters an