pandas笔记

import pandas as pd
df = pd.DataFrame([  
            ['green', 'M', 10.1, 'class1'],   
            ['red', 'L', 13.5, 'class2'],   
            ['blue', 'XL', 15.3, 'class1']])  
df.columns = ['color', 'size', 'prize', 'class label']  
size_mapping = {  
           'XL': 3,  
           'L': 2,  
           'M': 1}  
df['size'] = df['size'].map(size_mapping)  
class_mapping = {label:idx for idx,label in enumerate(set(df['class label']))} 
df['class label'] = df['class label'].map(class_mapping) 
df
pd.get_dummies(df)