一个以上的构造函数 python class

Question

I come from the Java programming language and I know that you can have more than one constructor there.

My question now is: is that also possible in Python?

My Problem:

I have a class, where I have my help functions for my commands (implemented with click ). These commands are not in the history class. Now my commands sometimes only have an input_dir and an output_file without a temp_file . Or just an input_dir and output_file .

How can I still use the same constructor with 3 or sometimes 2 input parameters?

Answer 1

There is no such thing as method overloading in python. Hence, it is impossible to have multiple constructors as you desire. You can however make the arguments optional.

class History():
    def __init__(self, input_dir=None, output_file=None, temp_file=None):
        self._input_dir = input_dir
        self._output_file = output_file
        self.temp_file = temp_file

    def identify_ID(self):
        '''Identifies the ID'''

This will alow any combination of your arguments to work. This would leave the method you are calling up to making sense of the instance's variables.