I have a function that takes a tuple of different lengths as an argument:
from typing import Tuple
def process_tuple(t: Tuple[str]):
# Do nasty tuple stuff
process_tuple(("a",))
process_tuple(("a", "b"))
process_tuple(("a", "b", "c"))
When I annotate function like mentioned above, I get these error messages
fool.py:9: error: Argument 1 to "process_tuple" has incompatible type "Tuple[str, str]"; expected "Tuple[str]"
fool.py:10: error: Argument 1 to "process_tuple" has incompatible type "Tuple[str, str, str]"; expected "Tuple[str]"
process_tuple
really works with tuples and I use them as immutable lists of variable length. I haven't found any consensus on this topic on the internet, so I wonder how should I annotate this kind of input.
Variable length homogeneous tuple we can annotate using ...
literal (aka Ellipsis
) like
def process_tuple(t: Tuple[str, ...]):
...
after that errors should go away.
From docs
To specify a variable-length tuple of homogeneous type, use literal ellipsis, e.g.
Tuple[int, ...]
. A plainTuple
is equivalent toTuple[Any, ...]
, and in turn totuple
.