流程控制
顺序流程: 每一行代码都会执行, 并且只会执行一次
...
if -- else 结构语句:
1,if 布尔表达式:
代码对齐, tab 与空格不能够同时出现
2,if 布尔表达式:
代码
- else:
- money = input ('please input your money:')
- if money> 100:
- print 'you are vip!'
- print 'you are gold VIP'
- else :
- print('you are not vip!')
3,if--else 嵌套:
if 布尔表达式:
代码
else:
if 布尔表达式:
代码
else:
代码
- ....
- money = input ('please input your money:')
- if money> 100:
- print 'you are vip!'
- if money>= 200:
- print 'you are golden VIP'
- if 200>money>100:
- print'you are silver vip'
- else :
- if money<0:
- print'error!'
- else:
- print('you are not vip!')
4,if 布尔表达式:
代码
elif 布尔表达式:
代码
- money = input ('please input your money:')
- if money> 100:
- print 'you are vip!'
- if money>= 200:
- print 'you are golden VIP'
- if 200>money>100:
- print'you are silver vip'
- elif money<0:
- print'error!'
- else:
- print('you are not vip!')
- EG:
第一种:
- #coding:UTF-8
- score = int(input('please input a score:'))
- if 100>=score>=90:
- print('很好')
- if 90>=score>=70:
- print('well done!')
- if 70>=score>=60:
- print('pass!')
- if 60>score:
- print('failed!')
- if score>100 or score<0:
- print ('error!')
第二种:
- -- coding: cp936 --
- score = int(input('please input a score:'))
- if 100>=score>=90:
- print('很好')
- else:
- if 90>=score>=70:
- print('良好')
- else:
- if 70>=score>=60:
- print('及格')
- else:
- if 60>score>=0:
- print('不及格')
- else:
- print ('error!')
第三种:
- score = int(input('your number:'))
- if 100>=score>=90:
- print('excellent')
- elif 90>=score>=70:
- print('good')
- elif 70>=score>=60:
- print('pass')
- elif 60>score>=0:
- print('flunk')
- else:
- print ('error!')
循环流程
..while 循环
重复运行某些代码
1, 语法:
while 布尔表达式:
代码:(循环体)
注意: 要避免死循环(注意循环跳出条件)
服务器就是死循环 724365
- num = 0
- while num<10:
- print 'hello world!'
- num+=1
.....for 循环
1, 语法:
for 目标 in 表达式:
循环体
目标: 变量
表达式: 字符串, 列表, 元祖 ---- 可迭代对象
- a = 'baizhi'
- for i in a:
- print i
- teacher = ['fei','xige','kuai']
- for i in teacher:
- print i
- number = [123,466,969]
- for i in number:
- print i
- .range()
语法:
range([start],stop[,step=1])
1, 这个函数有三个参数, 其中方括号表示可选择参数()
2, 第一个参数默认就是 0, 第二个参数停止, 第三默认 1
3, 作用生成一个值, 从 start 开始, 到 stop 结束的数字序列
取值范围从 [start,stop) 左闭右开
- a = range(0,3,1)
- >> a
- [0, 1, 2]
- >>
- >> a=range(0,10,2)
- >> a
- [0, 2, 4, 6, 8]
- >> a = range(0,10,3)
- >> a
- [0, 3, 6, 9]
- >> range(3)
- [0, 1, 2]
- for i in range(5):
- print i
- 01
- 2
- 3
- 4
- >> for i in range(2,5):
- print i
- 2
- 3
- 4
- >> for i in range(1,5,2):
- print i
- 1
- 3
- ..break
跳出当前循环, 后面所有循环都不执行
- while True:
- num = input('please input your number:')
- if num ==1:
- break
- print('error,try again!')
- please input your number:3
- error,try again!
- please input your number:1
- .continue
跳过本次循环, 不影响下次循环
- for i in range(10):
- if i%2!=0:
- continue
- print i
- 02
- 4
- 6
- 8
- >> for i in range(10):
- if i%2!=0:
- break
- print i
来源: http://www.bubuko.com/infodetail-2558094.html