Bug fix of no space in the result of to_string.

[Telomelonia]

Description

As mentioned in the issue, in the result of the to_string() function, there is no space between value and unit.So, I added a space between value and unit.

This pull request is to address ...

Fixes #7455

Close #14231

TODOS

• space in LaTex format
• fix for format = generic and unicode cases.
• centralize the bug fix on the unit rather than the format.

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[Telomelonia]

@pllim
As discussed in #14231 I have made the issue fix as in bug fix rather than a feature request

[mhvk]

@Telomelonia - thanks for this! Some small nitpicky comments only. With those, this will be all set.

[eerovaher]

With the changes this pull request is proposing the following works as it should:

>>> from astropy.coordinates import Angle
>>> Angle(5, unit="rad").to_string()
'5 rad'

But the following still produce a string without a space (it would be good to add a unit test analogous to one of these):

>>> Angle(5, unit="rad").to_string(format="unicode")
'5rad'
>>> Angle(5, unit="rad").to_string(format="generic")
'5rad'

It would seem that a space should not be added between the value and the unit if the format is "latex" or "latex_inline", or if the output is sexagesimal.

[mhvk]

Oops, indeed, this is more of a partial fix than I had realized! I think in principle there should be a space also for latex, etc. In #14231, I had suggested to use super() for the non-sexagesimal case, but a quick try caused more breakage than I had thought would be the case. Also Quantity.to_string() does not support unicode (see new issue #14386) and arguably does latex wrong in typesetting the degree symbol with a space in between it and the value (new issue #14385).

One option here may be to just keep it simple and focus on the generic format only -- i.e., only update this PR to also allow format='generic'.

[Telomelonia]

Oops, indeed, this is more of a partial fix than I had realized! I think in principle there should be a space also for latex, etc. In #14231, I had suggested to use super() for the non-sexagesimal case, but a quick try caused more breakage than I had thought would be the case. Also Quantity.to_string() does not support unicode (see new issue #14386) and arguably does latex wrong in typesetting the degree symbol with a space in between it and the value (new issue #14385).

One option here may be to just keep it simple and focus on the generic format only -- i.e., only update this PR to also allow format='generic'.

I think one way is to include every format possible where space is required, since few units don't require space like 32'48'' so there is too much if and else ... another possible way is to take the output from the function and check whether space should be given or not and if space is required then add 1 space else pass
The another task is to insert the space in the Latex part

[mhvk]

My sense is still that apart from sexagesimal, this should all be handled by Quantity.to_string(). It may not be that tricky if we require that the latex and unicode entries for unit formats include whether a space is needed -- may need to edit things like Å and Ω -- or simply special-case the few that do not.

My sense, though, is not to let that stand in the way of doing the smaller change here, which solves things mostly.

[mhvk]

@Telomelonia - I squashed your commits and added an extra one that also adds a space for other formats. I think this way it is ready to go in!

@eerovaher - would you mind having another look? I think your comment is now addressed.

[mhvk]

Hopefully now got the visualization.wcsaxis bugs - should have tested locally with matplotlib installed...

[pllim]

Are the "TODO"s in original post above still relevant?

[mhvk]

@pllim - I think they're basically done with my additional commit, so I ticked them.

Requested changes have been implemented

[pllim]

Thanks, all!

[Telomelonia]

@Telomelonia - I squashed your commits and added an extra one that also adds a space for other formats. I think this way it is ready to go in!

Thank you all for assisting me