Source:

<br /> #!/bin/env python<br /> # coding=gb2312<br /> # -*- coding: gb2312 -*-<br /> from __future__ import division<br /> #### if-else ####<br /> print '#### if-else ####'<br /> a = input("a: ") # 12 or 10+2<br /> b = input("b: ")<br /> if(a>b):<br /> print "max: ", a<br /> else:<br /> print "max: ", b<br /> #### if-elif-else ####<br /> print '#### if-elif-else ####'<br /> score = raw_input("score: ") # string<br /> score = int(score)<br /> if(score>=90) and (score<=100):<br /> print "A"<br /> elif(score>=80 and score<90):<br /> print "B"<br /> elif(score>=60 and score<80):<br /> print "C"<br /> else:<br /> print "D"<br /> #### switch I ####<br /> print '#### switch ####'<br /> x = 1<br /> y = 2<br /> operator = "/"<br /> result = {<br /> "+": x+y,<br /> "-": x-y,<br /> "*": x*y,<br /> "/": x/y<br /> }<br /> print result.get(operator)<br /> #### switch II ####<br /> print '#### switch II ####'<br /> class switch(object):<br /> def __init__(self, value): # init value<br /> self.value = value<br /> self.fall = False # no break, then fall=False<br /> def __iter__(self):<br /> yield self.match # match method to create<br /> raise StopIteration # exception to check loop<br /> def match(self, *args):<br /> if self.fall or not args:<br /> return True<br /> elif self.value in args: # successful<br /> self.fall = True<br /> return True<br /> else: # fail<br /> return False<br /> operator = "+"<br /> x = 1<br /> y = 2<br /> for case in switch(operator):<br /> if case('+'):<br /> print x+y<br /> break<br /> if case('-'):<br /> print x-y<br /> break<br /> if case('*'):<br /> print x*y<br /> break<br /> if case('/'):<br /> print x/y<br /> break<br /> if case():<br /> print 'NULL'<br />

Result:

$


python if_else.py

#### if-else ####

a: 12 + 8

b: 30

max:  30

#### if-elif-else ####

score: 88

B

#### switch ####

0.5

#### switch II ####

3

================================================================

中文注释参考：

一个极小的问题。在python代码中，用了中文注释，不能被python解释器理解(python 2.5)。解决方案是:

# coding=gb2312



print 'ok'   # 中文注释没问题

或者:

# -*- coding: gb2312 -*-



print 'ok'  #这样也行

if-else 多种用法

#!/usr/bin/python
# -*- coding:utf8 -*- 
#
# blog.ithomer.net


a, b, c = 1, 2, 3

# 常规
def test1():
    if a>b:
        c = a
    else:
        c =b
    print c

# 表达式
def test2():
    c = a if a>b else b
    print c

# 二维列表
def test3():
    c = [b,a][a>b]
    print c

# 黑客用法
def test4():
    c = (a>b and [a] or [b])[0]
    print c

if __name__ == "__main__":
    test1()
    test2()
    test3()
    test4()

运行结果：

2

2

2

2

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