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concat & append

import pandas as pddf1 = pd.DataFrame({'A':['A0', 'A1', 'A2'],                    'B': ['B0', 'B1', 'B2'],                    'C': ['C0', 'C1', 'C2']})# print(df1)df2 = pd.DataFrame({'A':['A3', 'A4', 'A5'],                    'B': ['B3', 'B4', 'B5'],                    'C': ['C3', 'C4', 'C5']})# print(df2)# 连接多个 DataFramedf = pd.concat([df1, df2], ignore_index=True)print(df)df = df1.append(df2, ignore_index=True)print(df)

merge

import pandas as pddf1 = pd.DataFrame({'Key':['K0', 'K1', 'K2'],                    'A': ['A0', 'A1', 'A2'],                    'B': ['B0', 'B1', 'B2']})print(df1)print('--------------------------')df2 = pd.DataFrame({'Key':['K0', 'K1', 'K2', 'K3'],                    'C': ['C0', 'C1', 'C2', 'C3'],                    'D': ['D0', 'D1', 'D2', 'D3']})print(df2)print('--------------------------')# 连接多个 DataFramedf = pd.merge(df1, df2, how='inner', on='Key')print(df)df = pd.merge(df1, df2, how='left', on='Key')print(df)df = pd.merge(df1, df2, how='right', on='Key')print(df)df = pd.merge(df1, df2, how='outer', on='Key')print(df)

join

import pandas as pddf1 = pd.DataFrame({'A': ['A0', 'A1', 'A2'],                    'B': ['B0', 'B1', 'B2']},                   index=['K0', 'K1', 'K2'])print(df1)print('--------------------------')df2 = pd.DataFrame({'C': ['C0', 'C1', 'C2', 'C3'],                    'D': ['D0', 'D1', 'D2', 'D3']},                   index=['K0', 'K1', 'K2', 'K3'])print(df2)print('--------------------------')# 连接多个 DataFramedf = df1.join(df2, how='inner')print(df)df = df1.join(df2, how='left')print(df)df = df1.join(df2, how='right')print(df)df = df1.join(df2, how='outer')print(df)

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