Sensible array outputs for pygmt info

[weiji14]

Description of proposed changes

Output the result of pygmt.info as a numpy.ndarray when either of per_column (C), spacing (I), or nearest_multiple (T) are used. This would be more usable that a raw string that is meant for the command line world.

This implements @seisman's original suggestion at #147 (comment), with both 1D and 2D array outputs supported!

Examples:

import pygmt

table = pygmt.datasets.load_ocean_ridge_points()

info(table=table, per_column=True)  # for basemap region -R
# array([-179.9401,  179.935 ,  -65.6182,   86.8   ])

info(table=table, nearest_multiple=0.1)  # for makecpt series -T
# array([-1.8e+02,  1.8e+02,  1.0e-01])

info(table=table, spacing=0.1)  # for basemap region -R
# array([-180. ,  180. ,  -65.7,   86.8])

info(table=table, spacing="b")  # for plot -Ap
# array([[-179.9401,  -65.6182],
#        [ 179.935 ,  -65.6182],
#        [ 179.935 ,   86.8   ],
#        [-179.9401,   86.8   ],
#        [-179.9401,  -65.6182]])

The parsing uses a bit of regex to remove the "-R", "-I" from the raw string, and split on "/" or " " delimiters.

pygmt/pygmt/modules.py

Lines 125 to 130 in 05a3f23

	if any(arg in kwargs for arg in ["C", "I", "T"]):
	# Converts certain output types into a numpy array
	# instead of a raw string that is less useful.
	result = np.loadtxt(
	re.sub(pattern="-R|-T|/", repl=" ", string=result).splitlines()
	)

Note: Merge after #574!!! ✔️

Fixes #147

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

[weiji14]

Cool, thanks for reviewing, this will be a great addition for v0.2.0! I'll temporarily disable the required Windows Py3.8 test (random unrelated failure we should investigate at some point) to merge this (because I don't want to waste another 15min of CI resources).