Python3 0-127的ASCII 码和 Unicode码相同

可以直接利用ord()读取每个字符的ASCII码
a = input()
L = [0 for i in range(128)]
for i in range(len(a)):
if 0 <= ord(a[i]) <= 128:
L[ord(a[i])] += 1
flag = 0
for i in range(128):
if L[i] != 0:
flag += 1
print(flag)