标签：style blog color io 使用 ar strong sp div
Python中是没有switch的, 所以有时我们需要用switch的用法, 就只能通过if else来实现了. 但if else写起来比较冗长,
这时就可以使用Python中的dict来实现, 比switch还要简洁. 用法如下:
如果是key1的情况就执行func1, 如果是key2的情况就执行func2...(func1, func2...所有的函数的参数形式需要相同),
假设各个函数参数均为(arg1, arg2):
dictName = {"key1":func1, "key2":func2, "key3":func3"...} #字典的值直接是函数的名字,不能加引号
dictName[key](arg1, arg2)
示例代码如下:
#!/usr/bin/python #File: switchDict.py #Author: lxw #Time: 2014/10/05 import re 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 main(): inStr = raw_input("Please input the easy expression:(e.g. 1 + 2.But 1 + 2 + 3 are not accepted.\n") inList = re.split("(\W+)", inStr) inList[1] = inList[1].strip() print("-------------------------") print(inList) print("-------------------------") #Method 1: if inList[1] == "+": print(add(int(inList[0]), int(inList[2]))) elif inList[1] == "-": print(sub(int(inList[0]), int(inList[2]))) elif inList[1] == "*": print(mul(int(inList[0]), int(inList[2]))) elif inList[1] == "/": print(div(int(inList[0]), int(inList[2]))) else: pass #Method 2: try: operator = {"+":add, "-":sub, "*":mul, "/":div} print(operator[inList[1]](int(inList[0]), int(inList[2]))) except KeyError: pass if __name__ == ‘__main__‘: main()
Output:
PS J:\> python .\switchDict.py Please input the easy expression:(e.g. 1 + 2.But 1 + 2 + 3 are not accepted. 1 + 2 ------------------------- [‘1‘, ‘+‘, ‘2‘] ------------------------- 3 3 PS J:\> python .\switchDict.py Please input the easy expression:(e.g. 1 + 2.But 1 + 2 + 3 are not accepted. 4 - 9 ------------------------- [‘4‘, ‘-‘, ‘9‘] ------------------------- -5 -5 PS J:\> python .\switchDict.py Please input the easy expression:(e.g. 1 + 2.But 1 + 2 + 3 are not accepted. 6 / 5 ------------------------- [‘6‘, ‘/‘, ‘5‘] ------------------------- 1 1 PS J:\> python .\switchDict.py Please input the easy expression:(e.g. 1 + 2.But 1 + 2 + 3 are not accepted. 1 9 9 ------------------------- [‘1‘, ‘‘, ‘9‘, ‘ ‘, ‘9‘] ------------------------- PS J:\> python .\switchDict.py Please input the easy expression:(e.g. 1 + 2.But 1 + 2 + 3 are not accepted. 1 ( 9 ------------------------- [‘1‘, ‘(‘, ‘9‘] ------------------------- PS J:\>
个人感觉, 如果想用switch来解决某个问题, 并且每种情况下的操作在形式上是相同的(如都执行某个函数并且这些函数有
相同的参数), 就可以用这种方法来实现.
标签：style blog color io 使用 ar strong sp div
原文地址：http://www.cnblogs.com/lxw0109/p/Python-funcName-DictValue.html
