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python学习笔记二:流程控制

时间:2014-12-22 16:12:37      阅读:213      评论:0      收藏:0      [点我收藏+]

标签:

一、if else:

#!/usr/bin/python
x = int(raw_input(please input:))


if x >= 90:
    if x >= 95:
        print a+
    else:
        print a
elif x >= 80:
    if x >= 85:
        print b+
    else:
        print b
elif x >= 70:
    if x >= 75:
        print c+
    else:
        print c
else:
    if x >= 60:
        print d+
    else:
        print bad

二、逻辑运算符 and or not

#!/usr/bin/python
x = int(raw_input(please input x:))
y = int(raw_input(please input y:))


if x >= 90 and y >= 90:
    print a
elif x >= 80 or y >= 80:
    print b
elif not x < 60 and (not y < 60):
    print c
else:
    print bad

三、for

序列:

#!/usr/bin/python

s = "hello python"

for x in s:
    print x

for index in range(len(s)):
    print s[index]

字典:

#!/usr/bin/python

dic = {a:1,b:2,c:3}

for x in dic:
    print x,dic[x]

for k,v in dic.items():
    print k,v

控制

else:for正常执行完会执行else中的内容,否则不会(如下面的代码执行过程按Ctrl+c)

#!/usr/bin/python
import time

for x in range(10):
    print x
    time.sleep(1)
else:
    print end

break:跳出当前这层循环

#!/usr/bin/python
for x in range(10):
    print x
    if x == 6:
        break
else:
    print end

这里不会执行else中的内容

pass:占位

exit:退出

#!/usr/bin/python
for x in range(10):
    print x
    if x == 2:
        print hello,x
        continue
    if x == 4:
        pass
    if x == 5:
        exit()
    if x == 6:
        break
    print **10
else:
    print end

四、while

 当条件失败,正常结束会执行,执行break后else中不执行

#!/usr/bin/python

x = hello

while x != "q":
    print x
    x = raw_input(please input something,q for quit:)
    if not x:
        break
else:
    print ending

 

python学习笔记二:流程控制

标签:

原文地址:http://www.cnblogs.com/lurenjiashuo/p/python-note-ifelse-for-while.html

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