from sklearn.preprocessing import LabelEncoder
import pandas as pd

# Example dataset
data = pd.DataFrame({
    'color': ['red', 'green', 'blue', 'blue', 'green', 'red'],
    'size': ['S', 'M', 'M', 'L', 'S', 'S'],
    'price': [10, 15, 20, 25, 10, 15]
})

# Create LabelEncoder object
le = LabelEncoder()

# Encode categorical columns
data['color'] = le.fit_transform(data['color'])
data['size'] = le.fit_transform(data['size'])

# Display preprocessed data
print(data)