python tuples: unpacking into a list using *args

Question

Hello and thanks for your time;

I am using *args to take various arguments, which creates a tuple. How do I 'unpack' a tuple into a list? The following code appends the list with a tuple.

grades = []

def add_grades(*args):
    grades.append(args):
    return grades

print(add_grades(99,88,77))

I can do this using a for loop and iterating through the tuple, but looking to see if I can unpack directly.

I could, but this just creates a list, whereas I already have a list created and trying to append values. — JulienEast, Feb 16 '20 at 19:08
Ah, you’re trying to append multiple values, I misunderstood. — AMC, Feb 16 '20 at 19:09
Might this be a duplicate of https://stackoverflow.com/questions/3274095/append-tuples-to-a-list ? — AMC, Feb 16 '20 at 19:10
I didn't think so (I could be wrong?) since I am specifically using *args and trying to append multiple values to an already existing list. But I will review. — JulienEast, Feb 16 '20 at 19:12
The question is slightly confusing, but the accepted answer is just `list.extend()`. — AMC, Feb 16 '20 at 19:13

score 5 · Accepted Answer · answered Feb 16 '20 at 18:51

5

You can use the list.extend method instead:

def add_grades(*args):
    grades.extend(args):
    return grades

answered Feb 16 '20 at 18:51

blhsing

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Guy · Answer 2 · 2020-02-16T19:58:23.367

3

To convert the tuple to list you can return *args as list and extend the existing list

grades = []

def add_grades(*args):
    return [*args]

grades.extend(add_grades(99,88,77))

Note that you can extend the list with tuple as well

def add_grades(*args):
    return args

grades.extend(add_grades(99,88,77))

If you don't do anything else in add_grades you can also do it without any function

grades.extend([99,88,77])

edited Feb 16 '20 at 19:58

answered Feb 16 '20 at 18:54

Guy

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Thanks - it seems that extend() takes any tuple arguments and adds them to a list, which was what I was looking for (and included in the two first answers) – JulienEast Feb 16 '20 at 19:30

python tuples: unpacking into a list using *args

2 Answers2