Python ยท Chapter 21 of 45
*args and **kwargs
`*args` collects extra POSITIONAL arguments into a tuple. `**kwargs` collects extra KEYWORD arguments into a dict.
Use them when a function needs to accept a flexible number of arguments.
*args
The star unpacks/packs positional arguments. Inside the function `args` is a tuple.
**kwargs
Two stars unpack/pack keyword arguments. Inside the function `kwargs` is a dict.
Example 1 (python)
def total(*nums):
return sum(nums)
print(total(1, 2, 3, 4))Output
10*nums packs all positional args into a tuple.
Example 2 (python)
def profile(**info):
for k, v in info.items():
print(k, "=", v)
profile(name="Ana", age=25)Output
name = Ana
age = 25**info collects keyword args into a dict.
Key points
- *args -> tuple of extra positional args.
- **kwargs -> dict of extra keyword args.
- Names `args`/`kwargs` are convention, not required.
- Order: normal, *args, **kwargs.
๐ก Note: You can also USE `*` and `**` to UNPACK an iterable/dict into function arguments: `f(*mylist)`, `f(**mydict)`.