ENH: pd.NamedAgg should accept args and kwargs

[WillAyd]

Feature Type

• Adding new functionality to pandas

• Changing existing functionality in pandas

• Removing existing functionality in pandas

Problem Description

This part of the API seems inconsistent:

In [24]: df = pd.DataFrame({"group": list("aab"), "val1": range(3)})
In [28]: def n_between(ser, low, high):
    ...:     return ser.between(low, high).sum()
    ...: 

In [29]: df.groupby("group")["val1"].agg(n_between, 0, 1)  # works
Out[29]: 
group
a    2
b    0
Name: val1, dtype: int64

In [30]: df.groupby("group").agg(n_between=pd.NamedAgg("val1", n_between, 0, 1))
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[30], line 1
----> 1 df.groupby("group").agg(n_between=pd.NamedAgg("val1", n_between, 0, 1))

TypeError: NamedAgg.__new__() takes 3 positional arguments but 5 were given

Feature Description

NamedAgg should forward along *args and **kwargs just like the normal callable function application can

Alternative Solutions

status quo

Additional Context

No response

[rhshadrach]

Perhaps it's obvious, but feels worth stating: this would also enable the use of a list with different args/kwargs for each element.

+1

[tomhoq]

take

[haiyashah]

take

[tomhoq]

Hi @haiyashah ! I already had this issue assigned and in the meanwhile have put some time into it. Would you mind taking another issue instead to avoid one of us wasting their time?
Thank you for your understanding,
Tomaz