Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['6937', '5429', '7795', 'Y', 't', 'W', '2243', '9007', 'r']

6937, 5429, 7795, 25, 20, 23, 2243, 9007, 18