• if
s = input()
score = int(s)

if score >= 80:
    print('A')
elif score < 80 and score >= 60:
    print('B')
else:
    print('C')

另外，if判断一个变量时，只要是非零、非空字符串、非空list就是True

  • for
items = ['a', 'b', 'c']
for i in items:
    print(i)

还可以用range()生成一个包含连续数字的list，range(x)的范围是0到x-1

sum = 0
for i in range(5):
    sum = sum + i
print(sum)

结果是10

  • while
sum = 0
i = 4

while i > 0:
    sum = sum + i
    i = i - 1

print(sum)

结果也是10

---> Python学习笔记目录