Annotating seaborn lineplot legend with number of rows for each category

Question

I want to get and show the number of rows of each type in a seaborn lineplot. Eg

import seaborn as sns
fmri = sns.load_dataset("fmri")
ax = sns.lineplot(x="timepoint", y="signal", hue="event", data=fmri)

I want to show the number of rows with event 'stim' and number of rows with event 'cue' as an addition to the legend eg instead of showing 'stim' in the legend, it could show 'stim (23)' meaning that 23 rows have the event as 'stim'

Answer 1

Something like this would do the trick:

fmri = sns.load_dataset("fmri")
x_col = 'timepoint'
y_col = 'signal'
hue_col = 'event'

ax = sns.lineplot(x=x_col, y=y_col, hue=hue_col, data=fmri)
handles,labels = ax.get_legend_handles_labels()
counts = fmri[hue_col].value_counts()
# labels[0] is used for the title by seaborn
new_labels = [labels[0]]+['{:s} ({:d})'.format(l, counts[l]) for l in labels[1:]]
ax.legend(handles, new_labels)