python中的for循环
如果没有for循环,项目依次打印字符串中的每个字符,用while循环实现会很麻烦
s = 'abcdefghijklmn ' number = len(s) while number: print(s[-number]) number -= 1 a b c d e f g h i j k l m n
或者
unmber = 0
while number < len(s):
print(s[index])
number += 1
使用for就方便多了
s = 'abcdefghijklmn ' for i in s: print(i)
a
b
c
d
e
f
g
h
i
j
k
l
m
n
for i in s:
print(i)
if i == 'c':
break
a
b
c
与while循环中一样,与else搭配,只要循环没有被break打断,就执行else
s = 'abcdefghijklmn ' for i in s: print(i) if i == 'c': break else: #被break打断就不执行else print('777') a b c