How do I print percentages in matplotlib-venn diagrams?

Question

By default matplotlib-venn's venn3 prints counts in each overlap. How do I print percentages instead?

Answer 1

I figured it out. Just divide each label by the total:

from matplotlib_venn import venn3

subsets = (1, 1, 1, 2, 1, 2, 2)
total = sum(subsets)
venn = venn3(subsets=subsets, set_labels=('Set1', 'Set2', 'Set3'))

for id in [''.join(map(str, i)) for i in product([0, 1], [0, 1], [0, 1])]:
    if id == '000':
        continue

    count = int(venn.get_label_by_id(id).get_text())
    venn.get_label_by_id(id).set_text('{:.1%}'.format(count / total))

Answer 2

A cleaner way is to use the subset_label_formatter argument, as described in this answer: https://stackoverflow.com/a/53490475/4133418

It would look something like this:

venn = venn3(subsets=subsets, set_labels=('Set1', 'Set2', 'Set3'),
             subset_label_formatter=lambda x: f"{(x/total):1.0%})