python学习笔记四：lambda表达式和switch

一、定义

lambda arg1,arg2... : returnValue

二、示例

#!/usr/bin/python

def f(x,y):
    return x*y

print f(2,3)
#

g = lambda x,y:x*y
print g(2,3)
#

三、switch的一种实现方案

#!/usr/bin/python

from __future__ import division

#a=int(raw_input('please input num1:'))
#b=int(raw_input("please input num2:"))

def jia(x,y):
    return x+y

def jian(x,y):
    return x-y

def cheng(x,y):
    return x*y

def chu(x,y):
    return x/y

def operator(x,o,y):
    if o == '+':
        print jia(x,y)
    elif o == '-':
        print jian(x,y)
    elif o == '*':
        print cheng(x,y)
    elif o == '/':
        print chu(x,y)
    else:
        pass

operatord = {'+':jia,'-':jian,'*':cheng,'/':chu}

def switchoperator(x,o,y):
    print operatord.get(o)(x,y)

operator(2,'+', 4)
operator(2,'-', 4)
operator(2,'*', 4)
operator(2,'/', 4)

switchoperator(2,'+', 4)
switchoperator(2,'-', 4)
switchoperator(2,'*', 4)
switchoperator(2,'/', 4)