pandas concat 合并 Dataframe 数据

import pandas as pd

df1 = pd.DataFrame({
    
    'A': ['A0', 'A1', 'A2', 'A3'],
                    'B': ['B0', 'B1', 'B2', 'B3'],
                    'C': ['C0', 'C1', 'C2', 'C3'],
                    'D': ['D0', 'D1', 'D2', 'D3']},
                   index=[0, 1, 2, 3])
df1

df2 = pd.DataFrame({
    
    'A': ['A4', 'A5', 'A6', 'A7'],
                    'B': ['B4', 'B5', 'B6', 'B7'],
                    'C': ['C4', 'C5', 'C6', 'C7'],
                    'D': ['D4', 'D5', 'D6', 'D7']},
                   index=[4, 5, 6, 7])
df2

纵向合并

result1 = pd.concat(
    [df1, df2],
    axis=0  # 纵向合并
)
result1

横向合并

df1

df3 = pd.DataFrame({
    
    'E': ['E4', 'E5', 'E6', 'E7'],
                    'F': ['F4', 'F5', 'F6', 'F7'],
                    'G': ['G4', 'G5', 'G6', 'G7'],
                    'H': ['H4', 'H5', 'H6', 'H7']},
                   index=[0, 1, 2, 3])
df3

result2 = pd.concat(
    [df1, df3],
    axis=1 # 横向合并
)
result2

并集(默认)

df1

df4 = pd.DataFrame({
    
    'B': ['B2', 'B3', 'B6', 'B7'],
                    'D': ['D2', 'D3', 'D6', 'D7'],
                    'F': ['F2', 'F3', 'F6', 'F7']},
                   index=[2, 3, 6, 7])
df4

result3 = pd.concat(
    [df1, df4], # 合并
    axis=1, # 横向合并
    join = 'outer' # 并集
)
result3

交集

df1

df4

result4 = pd.concat(
    [df1, df4], # 合并
    axis=1, # 横向合并
    join = 'inner' # 交集
)
result4