Data Science
Label Encoding for Ordinal Variables
Senior Data Analyst
May 3, 2026
5 min read
Label Encoding
from sklearn.preprocessing import LabelEncoder
le = LabelEncoder()
df['size_encoded'] = le.fit_transform(df['size']) # S=0, M=1, L=2
Manual Mapping (More Control)
size_map = {'Small': 1, 'Medium': 2, 'Large': 3}
df['size_num'] = df['size'].map(size_map)
*Day 124: Scaling and Normalization.*