第五次作业

str1 = "abcdefg"

print(str1[::-1])
str1_list = list(str1)
str1_list.reverse()
print(''.join(str1_list))

 

 a = "456789"

b = "123456789"

uk1 = list(a)

uk2 = list(b)

num = 0

for x in uk1:

    if True:

        num += 1

if num == len(uk1):

    print("a是b的子串")