API: should Series.get be strictly label based or allow positional?

[jorisvandenbossche]

The implementation of Series.get currenlty simply is:

def get(self, key, default=None):
    try:
        return self[key]
    except (KeyError, ValueError, IndexError):
        return default

So it is simply using [] / __getitem__ under the hood.

Somehow I think this is the expected thing, but the consequence is that it brings along all complexities of __getitem__ in pandas (whether to fallback to positional or not ..).

So, if we want, we could make get more strict by using loc under the hood (and it should be possible to do that with a deprecation in a first phase for those cases that loc raises but [] returns a value).

[jbrockmendel]

Discussed this on the dev call today, agreed we expect this to be label-based. No one felt strongly enough about this to want to deprecate the current behavior, but noted that if __getitem__ is deprecated (xref #50617) that will be a natural consequence. There was also mention of deprecating get entirely, which was also luke-warm (no one would object to it, but no one was actively interested)

[jbrockmendel]

Discussed on yesterday's dev call. I advocated deprecating get entirely, no one else seemed to like that idea. There was agreement that deprecating to limit to a scalar input would be an improvement.