The difference between these two cases are explained when also taking into consideration the initial PEP for extended unpacking: PEP 3132 — Extended iterable unpacking. In the Abstract for that PEP we can see that: This PEP proposes a change to iterable unpacking syntax, allowing to specify a “catch-all” name which will be assigned a … Read more
You need to explicitly make it a tuple (see the official tutorial): def returns_tuple_of_one(a): return (a, )
it’s typically referred to as flattening a nested structure. >>> tupleOfTuples = ((1, 2), (3, 4), (5,)) >>> [element for tupl in tupleOfTuples for element in tupl] [1, 2, 3, 4, 5] Just to demonstrate efficiency: >>> import timeit >>> it = lambda: list(chain(*tupleOfTuples)) >>> timeit.timeit(it) 2.1475738355700913 >>> lc = lambda: [element for tupl in … Read more
Unpacking in list, dict, set, and tuple literals has been added in Python 3.5, as described in PEP 448: Python 3.5.0 (v3.5.0:374f501f4567, Sep 13 2015, 02:27:37) on Windows (64 bits). >>> [1, 2, 3, *[4, 5, 6]] [1, 2, 3, 4, 5, 6] Here are some explanations for the rationale behind this change. Note that … Read more
A single star * unpacks a sequence or collection into positional arguments. Suppose we have def add(a, b): return a + b values = (1, 2) Using the * unpacking operator, we can write s = add(*values), which will be equivalent to writing s = add(1, 2). The double star ** does the same thing … Read more
This is PEP-448: Additional Unpacking Generalizations, which is new in Python 3.5. The relevant change-log is in https://docs.python.org/3/whatsnew/3.5.html#pep-448-additional-unpacking-generalizations: PEP 448 extends the allowed uses of the * iterable unpacking operator and ** dictionary unpacking operator. It is now possible to use an arbitrary number of unpackings in function calls: >>> >>> print(*[1], *[2], 3, *[4, … Read more
The single star * unpacks the sequence/collection into positional arguments, so you can do this: def sum(a, b): return a + b values = (1, 2) s = sum(*values) This will unpack the tuple so that it actually executes as: s = sum(1, 2) The double star ** does the same, only using a dictionary … Read more
You really don’t want your method to return Product since this is uselessly vague. If you want to be able to use the returned object as a tuple, then you’ll have to know its arity. So what you can do is have a series of toTupleN methods for different arities. For convenience, you can add … Read more
Return Series and it will put them in a DataFrame. def myfunc(a, b, c): do something return pd.Series([e, f, g]) This has the bonus that you can give labels to each of the resulting columns. If you return a DataFrame it just inserts multiple rows for the group.
In a function call *t means “treat the elements of this iterable as positional arguments to this function call.” def foo(x, y): print(x, y) >>> t = (1, 2) >>> foo(*t) 1 2 Since v3.5, you can also do this in a list/tuple/set literals: >>> [1, *(2, 3), 4] [1, 2, 3, 4] **d means … Read more