Compatibility break on joins

[CedricFR]

Hi,

The latest modifications to the join functions are breaking some usage code.

The incriminated changes are: bbe03e8...17b3440

The problem is this case:

df >> left_join(df2, by=["column1", "column2", "column3"])

It used to mean "merge based on those 3 columns", but now it means "merge based on column1 for left dataframe, and column2 on the right dataframe", which is quite different!

What's the rationale? Is it because we're now supposed to use tuples and not lists in those cases?

Either way, if we decide this is the way forward, it should be a major version change because it breaks one of the major use cases of dfply. What do you think?

[kieferk]

That's my fault. I changed it to fix another issue and didn't think about what the change implied in enough detail before pushing the change.

I'm at work now but I'll revert this tonight and come up with a way to fix the other issue a different way.

Sorry about that!

[kieferk]

OK hopefully the current push to master will resolve the issue. Let me know if not, obviously. Sorry for the inconvenience.