Python－if-elif-else语句

Source:

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

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

 

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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.neta, 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 cif __name__ == "__main__":    test1()    test2()    test3()    test4()

运行结果：
2
2
2
2

 

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