API: add a setattr method to NDFrame to assist with piping

I frequently come into situations where I have to break up piping, because piping doesn’t work on attributes:

>>> new_df = (df.groupby(...)
...             .pipe(...)
>>> new_df.index.name = 'index_name'
>>> new_df.columns = pd.CategoricalIndex(new_df.columns)
>>> new_df = new_df.pipe(...)  # and so on...

I think it would be cleaner if NDFrame had a setattr method that returns self. Then the above would become:

>>> new_df = (df.groupby(...)
...             .pipe(...)
...             .setattr('index.name', 'index_name')
...             .setattr('columns', lambda x: pd.CategoricalIndex(x.columns))
...             .pipe(...)  # and so on...
...             )

The first argument to .setattr is a string and can be dot-seperated, and the second parameter is called with self as its first argument if a callable.

I think this would make piping cleaner in many cases.

Opinions?

[mroeschke]

Overall I feel -1 on the idea of a generic setattr method. I would rather have set_axis (or any analogous method) to operate on self then have a setattr method able to modify anything on the frame.

[topper-123]

Closing. I don’t feel there is support for this.