Python中使用关键字传递位置参数后，如何向*args传递参数

Ah, I see the issue here! When you use keyword arguments for a and b, you can't just pass aa=(4,5,6) and expect it to go into the *aa parameter. That's because *aa is meant to catch extra positional arguments, not a keyword argument named aa—that would end up in **bb instead. Let me break this down and show you the right way to do it.

Why Your Current Call Isn't Working #

Let's take your example call:

fun(b=1,a=2,aa=(4,5,6),dd=4,pp=5)

In this case, aa=(4,5,6) is treated as a keyword argument, so it gets added to the **bb dictionary. If you run this, you'll see output like:

2
1
()
{'aa': (4, 5, 6), 'dd': 4, 'pp': 5}

Notice how aa is empty, and bb now has an entry for 'aa'? That's not what you want.

The Fix: Use the * Operator to Unpack Your Iterable #

To get those values into *aa, you need to unpack your tuple or list using the * operator when calling the function. This tells Python to treat each element in the iterable as a separate positional argument, which *aa will then collect.

Here are two valid ways to do this:

Unpack a Tuple #

fun(b=1,a=2,*(4,5,6),dd=4,pp=5)

Unpack a List #

fun(b=1,a=2,*[4,5,6],dd=4,pp=5)

Either way, when you run the function, you'll get the output you're expecting:

2
1
(4, 5, 6)
{'dd': 4, 'pp': 5}

Now *aa correctly holds the (4,5,6) tuple, and **bb only has the dd and pp key-value pairs.

Quick Recap #

• *aa collects extra positional arguments, not keyword arguments with the name 'aa'.
• To pass a group of values to *aa when using keyword args for other parameters, use * to unpack your iterable into individual positional args.

内容的提问来源于stack exchange，提问作者user2779311