由于 Python 没有 switch 语句，我应该使用什么？ [复制]

Question

可能重复：
Replacements for switch statement in python?

我正在用 Python 制作一个基于控制台的小应用程序，我想使用 Switch 语句来处理用户对菜单选择的选择。

你的兽医建议我用什么。谢谢！

Answer 1

有两种选择，第一种是标准的if ... elif ...链。另一种是将选择映射到可调用对象的字典（函数是子集）。取决于你在做什么，哪个更好。

elif 链

 selection = get_input()
 if selection == 'option1':
      handle_option1()
 elif selection == 'option2':
      handle_option2()
 elif selection == 'option3':
      some = code + that
      [does(something) for something in range(0, 3)]
 else:
      I_dont_understand_you()

字典：

 # Somewhere in your program setup...
 def handle_option3():
    some = code + that
    [does(something) for something in range(0, 3)]

 seldict = {
    'option1': handle_option1,
    'option2': handle_option2,
    'option3': handle_option3
 }

 # later on
 selection = get_input()
 callable = seldict.get(selection)
 if callable is None:
      I_dont_understand_you()
 else:
      callable()

Answer 2

使用字典将输入映射到函数。

switchdict = { "inputA":AHandler, "inputB":BHandler}

处理程序可以是任何可调用的。然后你像这样使用它：

switchdict[input]()

Answer 3

调度表，或者更确切地说是字典。

您也可以映射键。菜单选择的值到执行所述选择的功能：

def AddRecordHandler():
        print("added")
def DeleteRecordHandler():
        print("deleted")
def CreateDatabaseHandler():
        print("done")
def FlushToDiskHandler():
        print("i feel flushed")
def SearchHandler():
        print("not found")
def CleanupAndQuit():
        print("byez")

menuchoices = {'a':AddRecordHandler, 'd':DeleteRecordHandler, 'c':CreateDatabaseHandler, 'f':FlushToDiskHandler, 's':SearchHandler, 'q':CleanupAndQuit}
ret = menuchoices[input()]()
if ret is None:
    print("Something went wrong! Call the police!")
menuchoices['q']()

记得验证您的输入！ :)