Calling Python function with set of parameters from variable

Question

In my Python script I call this function a few times

write2db(int(pocnr), larm1, tid, label1, q1, x, y, lat, long, radio)

I want to be able to have the set of variables in one variable.

Should look like this

write2db(myargs)

So when I make a change to list of args I don't have to do it in more than one place. I have tried a few things but so far no luck. Any suggestions?

Possible duplicate of [How to extract parameters from a list and pass them to a function call](http://stackoverflow.com/questions/7527849/how-to-extract-parameters-from-a-list-and-pass-them-to-a-function-call) — juanpa.arrivillaga, Jan 16 '17 at 22:30
i feel stupid but i dont understand all the answers. To clear the question a bit. How do I define the myargs? I've tried to do it global as myargs = (int(pocnr), larm1, tid, label1, q1, x, y, lat, long, radio) but then the variables are not defined yet. — Stefan Rydberg, Jan 16 '17 at 22:51
There is an explicit example by denvaar. Also, **do not post code in comments. Why do you expect people to read your code in a comment, especially for python, where indentation is important?** — juanpa.arrivillaga, Jan 16 '17 at 22:52

score 2 · Accepted Answer · answered Jan 16 '17 at 22:34

2

You can use *args or **kwargs. The names args and kwargs don't actually matter, but its the * and ** that does the trick. Basically, * will unpack a list, and similarly, ** will unpack a dict.

*args is just a list of values in the same order as where you defined your function.

eg.

args = [23, 6, 2, "label", 5, 25, 21, 343.22, 111.34, 2]
write2db(*args)

**kwargs is a key-value mapping (python dict) of argument names to argument values

eg.

kwargs = {
    'pocnr': 23,
    'larm1': 21,
    # ... etc.
}
write2db(**kwargs)

answered Jan 16 '17 at 22:34

denvaar

2,174
2
22
26

So you think args = [int(pocnr), larm1, tid, label1, q1, x, y, lat, long, radio] will do the trick? – Stefan Rydberg Jan 16 '17 at 22:54
It did! Thanks alot. Now i can make my code more clean and easier to admin. – Stefan Rydberg Jan 16 '17 at 23:13

score 0 · Answer 2 · answered Jan 16 '17 at 22:32

0

You could create a namedtuple with each of those arguments, then get the arguments out by name inside of the function.

Or you could just use variable length argument *args, and then inside your function:

    for arg in args:
        # do something with arg

answered Jan 16 '17 at 22:32

Greg Jennings

1,611
16
25

1

You can just pass `f(*args)`. No need to change any definitions. – juanpa.arrivillaga Jan 16 '17 at 22:33

Calling Python function with set of parameters from variable

2 Answers2