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.

['5915', '3409', 'P', '6729', 'W', 'Y', '8945', '723', 'x', '7415', 'B', '3423', '6879', '2345', 'v']
5915, 3409, 16, 6729, 23, 25, 8945, 723, 24, 7415, 2, 3423, 6879, 2345, 22