Labelling axes

penguins provides a label_axes() function, which expects a list (or other iterable) of Axes objects.

For a typical “publication-style” labelling, the syntax can appear a bit unusual at first:

fig, axs = ...

...  # do your plotting here

pg.label_axes(axs, fstr="({})", fontweight="semibold")

The fstr parameter is a string which is then formatted with the label you are using, meaning that the curly braces {} are replaced with the label text. By default, penguins uses alphabetical labels, i.e. abcdef… although numeric labels and Roman numerals are also available. So, the curly braces inside the parentheses are replaced with this label and so what penguins gives you is labels which read (a), (b), and so on.

Other parameters such as fontweight are just passed directly to ax.text().

import penguins as pg

fig, axs = pg.subplots(1, 4, figsize=(4, 2))

pg.label_axes(axs, fstr="({})", fontweight="semibold")

If you don’t pass the fstr parameter, then by default only the label itself is printed (i.e. the letters) without anything around it. This style also sees some use in publications.

import penguins as pg

fig, axs = pg.subplots(1, 4, figsize=(4, 2))

pg.label_axes(axs, fontweight="semibold")

The documentation for label_axes() provides a few more options which you can use to customise the labelling (e.g. if you want to start from a different letter/number).