Matplotlib legend, add items across columns instead of down

Question

For a simple plot below, is there a way to make matplotlib populate the legend so that it fills the rows left to right, instead of first column then second column?

Answer 1

By default, the legend will fill all allocated columns before adding a new row. You can therefore re-order the handles and labels together to take advantage of this:

handles, labels = ax1.get_legend_handles_labels()
handles = np.concatenate((handles[::2],handles[1::2]),axis=0)
labels = np.concatenate((labels[::2],labels[1::2]),axis=0)