pandas快速创建映射以及逆映射方法

import pandas as pd
df = pd.DataFrame([['red', 'M', 10.1, 'type1'],
                   ['blue', 'L', 12.5, 'type1'],
                   ['white', 'XL', 13.3, 'type2']])

df.columns = ['color', 'size', 'price', 'type']
print(df)
# create a mapping of the different size
size_mapping = {'XL': 3,
                'L': 2,
                'M': 1}
# map them
df['size'] = df['size'].map(size_mapping)
print(df)
# make a inverse mapping
inv_size_mapping = {v: k for k, v in size_mapping.items()}
df['size'].map(inv_size_mapping)

result