Pythonic(OO)根据对象的类型选择类方法的方法

Question

有没有更好的Pythonic/面向对象的方式来选择在运行时执行哪个特定的类方法，这取决于对象的类型，因为使用type()方法被认为是不优雅的(？

我为我正在使用的三种数据类型编写了以下代码。它基本上将不同的函数存储在字典中作为值，将其与其相应的对象类型配对为键：

import pathlib
import _io
########################################
class choose_for :
def __init__(self, var):
func_dict = {str:self.func1, pathlib.WindowsPath:self.func2, _io.TextIOWrapper:self.func3}
self.func = func_dict[type(var)]
def func1(self) :
print("Because it is for STRING like n")
def func2(self) :
print("Because it is for PATH like n")
def func3(self) :
print("Because it is for FILE_POINTER like n")
def execute(self):
print("This object will be executed by : ", self.func)
self.func()
########################################
var1 = str("something")
var2 = pathlib.Path()
var3 = _io.open("file.txt")
########################################
chosen1 = choose_for(var1)
chosen1.execute()
chosen2 = choose_for(var2)
chosen2.execute()
chosen3 = choose_for(var3)
chosen3.execute()
########################################
var3.close()

它给出以下输出：

This object will be executed by :  <bound method choose_for.func1 of <__main__.choose_for object at 0x0000020A150A3088>>
Because it is for STRING like
This object will be executed by :  <bound method choose_for.func2 of <__main__.choose_for object at 0x0000020A1509EFC8>>
Because it is for PATH like
This object will be executed by :  <bound method choose_for.func3 of <__main__.choose_for object at 0x0000020A15276B48>>
Because it is for FILE_POINTER like

还有什么技术术语，对于我在这里试图做的事情？ 我认为这可能与单次调度、函数重载或多态性有关，但我不确定。

Answer 1

这确实是单调度，Python 通过functools模块支持。不需要上课。

from functools import singledispatch

@singledispatch
def execute(arg):
print(f"something with type {type(arg)}")
@execute.register(str):
def _(arg):
print("Because it is for STRING like n")
@execute.register(pathlib.Path):
def _(arg):
print("Because it is for PATH like n")
@execute.register(io.FileIO)
def _(arg):
print("Because it is for FILE_POINTER like n")

测试它，你会看到

>>> execute("something")
Because it is for STRING like
>>> execute(pathlib.Path())
Because it is for PATH like
>>> execute(_io.open("file.txt"))
Because it is for FILE_POINTER like
>>> execute(3)
something with type <class 'int'>

要将单调度与方法一起使用，请使用singledispatchmethod，它将调度方法的第二个参数，跳过隐式提供的实例或类参数。