Fixing issue with x axis label

[jpalm3r]

Previously, by default, the x positions of the skill plots were at [1, 2, 3, ..., n]. However, when an aux variable is numeric, that raised rendering issues (see issue #429).

This PR changes the handling of x labels in skill plots based on whether the x values are numeric or not.

[jsmariegaard]

Looks great - and I can confirm it works.

But could you please update the notebook "" to use this functionality :-)

You could change the cell

def _format_ax(ax, xlims, ylims):
    ax.set_xlim(*xlims)
    ax.set_ylim(*ylims)
    ax.set_xlabel("Lead time [days]", fontsize=12)
    ax.set_ylabel("MAPE [%]", fontsize=12)
    ax.legend(frameon=False, fontsize=12, bbox_to_anchor=(1.25, 0.7)),
    ax.tick_params(axis="both", which="major", labelsize=12)
    ax.set_title("Skill by lead time")
    ax.figure.autofmt_xdate(rotation=0, ha='center')
    
fig, ax = plt.subplots(1, 1, figsize=(8, 5))
sk.mape.plot.line(ax=ax, color=my_color_dict)
_format_ax(ax, xlims=(0, 7), ylims=(0, 10))
plt.show()

to something like

sk.mape.plot.line(title="Skill by lead time")

So at we would have at least one "example" of this :-)

[jpalm3r]

I do not understand.

This _format_ax() function in the notebook has nothing to do with the bug fixed in this PR. I created that function to consistently format all plots in my notebook.

If I implement sk.mape.plot.line(ax=ax, color=my_color_dict), then I get:

Which was already correct before the PR, since the lead time has a time step = 1. However, I wanted it a bit "prettier", so I made the formatting function.

[jsmariegaard]

Got it. Let's merge