小编HSR*_*RAO的帖子

alphabet = {'A':1, 'B': 2, 'C': 3, 'D':4, 'E': 5, 'F': 6, 'G':7, 'H':8, 'I':9, 'J':10,
            'K':11, 'L':12, 'M':13, 'N':14, 'O':15,'P': 16,'Q': 17,'R': 18,'S':19,'T':20,
            'U': 21, 'V':22, 'W':23, 'X': 24, 'Y':25, 'Z':26, ' ':27}

有没有办法将所有键转换为小写？注意:dict末尾有一个空格.