import seaborn as sns
df = sns.load_dataset('iris')
df['species'] = df['species'].astype('category').cat.codes
df.head(3)
'''sepal_length sepal_width petal_length petal_width species
5.1 3.5 1.4 0.2 0
4.9 3.0 1.4 0.2 0
4.7 3.2 1.3 0.2 0'''