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: ['7507', 'k', '6287', '1783', 'L', '4263', 'r', 'S', 'E', '789', 'I', 'x', 'g', 'u', '2149', 'G', '9657', 'b', 'W', '197', '4753', 'z', 'r', 'J']

7507, 11, 6287, 1783, 12, 4263, 18, 19, 5, 789, 9, 24, 7, 21, 2149, 7, 9657, 2, 23, 197, 4753, 26, 18, 10