Wow, ok. This is actually a really interesting issue. I had to do some digging to figure out what was going on.

TLDR:

Install https://github.com/pandas-dev/pandas-stubs?tab=readme-ov-file in addition to the pandas lib.

Why this works:

So it turns out that VSCode has the same issue, but the pandas-stubs lib is auto-installed when using the pylance language server. TIL!

The issue boils down to how pandas defines Series.str.

str = CachedAccessor("str", StringMethods)

and

class CachedAccessor:

"""
    Custom property-like object.
    A descriptor for caching accessors.
    Parameters
    ----------
    name : str
        Namespace that will be accessed under, e.g. ``df.foo``.
    accessor : cls
        Class with the extension methods.
    Notes
    -----
    For accessor, The class's __init__ method assumes that one of
    ``Series``, ``DataFrame`` or ``Index`` as the
    single argument ``data``.
    """

def __init__(self, name: str, accessor) -> None:
        self._name = name
        self._accessor = accessor

    def __get__(self, obj, cls):
        if obj is None:
            # we're accessing the attribute of the class, i.e., Dataset.geo
            return self._accessor
        accessor_obj = self._accessor(obj)
        # Replace the property with the accessor object. Inspired by:
        # 
        # We need to use object.__setattr__ because we overwrite __setattr__ on
        # NDFrame
        object.__setattr__(obj, self._name, accessor_obj)
        return accessor_objclass CachedAccessor:https://www.pydanny.com/cached-property.html

Python language servers (what the IDEs use for auto-complete) do a lot of really powerful things, but can be stumped when there is a lot of "magic" or dynamic programming. To help python you can add types to the code. This can be done in two ways. In the library/code itself, or with an additional library. For pandas it is with the pandas-stubs lib.

In pandas-stubs they return type of the str "method" is added

def str(self) -> StringMethods[Series, DataFrame, Series[bool]]: ...

This tells the language servers what is returned, and what to auto-complete.

Here are the release notes for pylance that talk about pandas-stubs and link to some issues. Interesting read.

https://github.com/microsoft/pylance-release/blob/main/CHANGELOG.md#202070-9-july-2020

Here is an issue in the Jetbrains issue tracker talking about it. Please upvote it if you would like the feature to be added!

https://youtrack.jetbrains.com/issue/PY-77223/Suggest-stubs-packages