How to customize seaborn.scatterplot legends?

Question

I plotted a scatterplot with seaborn library and I want to change the legend text but dont know how to do that.

example: The following is iris dataset with species columns encoded in 0/1/2 as per species.

plt.figure(figsize=(8,8))
pl = sns.scatterplot(x='petal_length', y ='petal_width', hue='Species', data=data, s=40,
                palette='Set1', legend='full')

I want to change the legends text from [0, 1, 2] to ['setosa', 'versicolor', 'virginica']. can anybody help.

Answer 1

First, Seaborn (and Matplotlib) usually picks up the labels to put into the legend for hue from the unique values of the array you provide as hue. So as a first step, check that the column Species in your dataframe actually contains the values "setosa", "versicolor", "virginica". If not, one solution is to temporarily map them to other values, for the purpose of plotting:

legend_map = {0: 'setosa',
              1: 'versicolor',
              2: 'virginica'}

plt.figure(figsize=(8,8))
ax = sns.scatterplot(x=data['petal_length'], y =data['petal_width'], hue=data['species'].map(legend_map), 
                     s=40, palette='Set1', legend='full')
plt.show()

Alternatively, if you want to directly manipulate the plot information and not the underlying data, you can do by accessing the legend names directly:

plt.figure(figsize=(8,8))
ax = sns.scatterplot(x='petal_length', y ='petal_width', hue='species', data=data, s=40,
                 palette='Set1', legend='full')
l = ax.legend()
l.get_texts()[0].set_text('Species') # You can also change the legend title
l.get_texts()[1].set_text('Setosa')
l.get_texts()[2].set_text('Versicolor')
l.get_texts()[3].set_text('Virginica')
plt.show()

This methodology allows you to also change the legend title, if need be.