Pass multiple arguments in form of tuple [duplicat

问题:

This question already has answers here:

What does ** (double star/asterisk) and * (star/asterisk) do for parameters? (21 answers)

Closed 4 years ago.

I'm passing a lot data around; specifically, I'm trying to pass the output of a function into a class and the output contains a tuple with three variables. I can't directly pass the output from my function (the tuple) into the class as in the input parameters.

How can format the tuple so it is accepted by the class without input_tuple[0], input_tuple[1], input_tuple[2]?

Here is a simple example:

#!/usr/bin/python

class InputStuff(object):

    def __init__(self, a, b, c):
        self.a = a
        self.b = b
        self.c = c


input_tuple = (1, 2, 3)
instance_1 = InputStuff(input_tuple)

# Traceback (most recent call last):
#   File "Untitled 3.py", line 7, in <module>
#     instance_1 = InputStuff(input_tuple)
# TypeError: __init__() takes exactly 4 arguments (2 given)

InputStuff(1, 2, 3)
# This works

回答1:

You can use the * operator to unpack the argument list:

input_tuple = (1,2,3)
instance_1 = InputStuff(*input_tuple)

回答2:

You are looking for: Unpacking Argument Lists

>>> range(3, 6)             # normal call with separate arguments
[3, 4, 5]
>>> args = [3, 6]
>>> range(*args)            # call with arguments unpacked from a list
[3, 4, 5]