Better handling of scalars to plt.subplot(). Fixes #880 - #1092

Realistically, I don't think I can spend the time on this PR to get this into 1.2.x. It's a pretty minor bug which I could live with in a 1.2 release. Agree?

As subplot is such a frequently used function, I'd like the benefit of having this in early in case there are any unexpected repercussions. So, yes, we should probably hang off -- but I wouldn't be opposed if it went in a few days late -- we have three weeks lead time until the rc1.

Ok. I will see what can be done.

I'm in favour of raising an exception if the user tries to pass in something that isn't an integer. Since this won't make it into 1.2, it's okay to break backwards compatibility.

On the other hand, it seems that passing nonintegers as indices to arrays does not raise an error:

>>> import numpy as np
>>> a = np.array([[1, 2], [3, 4]])
>>> a[0.1, 1.2]
2

Given that an error is not raised in this case, I can see the argument for supporting noninteger indices. Personally, though, I would never use this 'feature'.

Did we reach a consensus on this?

I think the consensus was that we should raise an Exception if int(v) != v.

@efiring That's what I thought. Thanks.

I'm not sure the 1.2.1 milestone is appropriate for this PR. Raising an exception if int(v) != v will break code, throwing an error were an error was not thrown before. Granted, I am of the opinion that I do not interpret passing a non-integer value as an index as anything but a programming error, but I feel the user should be warned in advance (e.g., by deprecating first) before making this change.

Not sure when it happened, but the problem no longer exists on master (could be from my own PR some time ago which related to projections, but I'm not certain).

This PR is therefore just an addition of a test.

I might have fixed it when I added code to detect if one might have
intended to use subplots() instead of subplot() and vice-versa. I forget
which PR that was, though.

I might have fixed it when I added code to detect if one might have intended to use subplots() instead of subplot() and vice-versa. I forget which PR that was, though.

Cool. Good job! 😄