标签：就是 sub import wrong sys gbk inpu bsp imp
字典的常用用途之一代替switch
在C/C++/Java语言中，有个很方便的函数switch，比如:
public class test {
public static void main(String[] args) {
String s = "C";
switch (s){
case "A":
System.out.println("A");
break;
case "B":
System.out.println("B");
break;
case "C":
System.out.println("C");
break;
default:
System.out.println("D");
}
}
}
在Python中要实现同样的功能，
方法一，就是用if, else语句来实现，比如:
from __future__ import division
def add(x, y):
return x + y
def sub(x, y):
return x - y
def mul(x, y):
return x * y
def div(x, y):
return x / y
def operator(x, y, sep=‘+‘):
if sep == ‘+‘: print add(x, y)
elif sep == ‘-‘: print sub(x, y)
elif sep == ‘*‘: print mul(x, y)
elif sep == ‘/‘: print div(x, y)
else: print ‘Something Wrong‘
print __name__
if __name__ == ‘__main__‘:
x = int(raw_input("Enter the 1st number: "))
y = int(raw_input("Enter the 2nd number: "))
s = raw_input("Enter operation here(+ - * /): ")
operator(x, y, s)
方法二，用字典来巧妙实现同样的switch的功能，比如:
#coding=gbk
from __future__ import division
x = int(raw_input("Enter the 1st number: "))
y = int(raw_input("Enter the 2nd number: "))
def operator(o):
dict_oper = {
‘+‘: lambda x, y: x + y,
‘-‘: lambda x, y: x - y,
‘*‘: lambda x, y: x * y,
‘/‘: lambda x, y: x / y}
return dict_oper.get(o)(x, y)
if __name__ == ‘__main__‘:
o = raw_input("Enter operation here(+ - * /): ")
print operator(o)
python 中无switch（写了几个函数代替switch）
标签：就是 sub import wrong sys gbk inpu bsp imp
原文地址：https://www.cnblogs.com/wen-/p/12168757.html
