How to join two tables horizontally or vertically in Python

1. Horizontal stitching

Horizontal splicing is to connect two tables by columns, that is, to expand the table by columns. Horizontal concatenation can be achieved using the concat() function in the pandas library.

import pandas as pd

# 创建两个表格
df1 = pd.DataFrame({
    
    'A': ['A0', 'A1', 'A2', 'A3'],
                    'B': ['B0', 'B1', 'B2', 'B3'],
                    'C': ['C0', 'C1', 'C2', 'C3'],
                    'D': ['D0', 'D1', 'D2', 'D3']})

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

# 将两个表格横向拼接
result = pd.concat([df1, df2], axis=1)

print(result)

Output result:

    A   B   C   D   A   B   C   D
0  A0  B0  C0  D0  A4  B4  C4  D4
1  A1  B1  C1  D1  A5  B5  C5  D5
2  A2  B2  C2  D2  A6  B6  C6  D6
3  A3  B3  C3  D3  A7  B7  C7  D7

2. Vertical stitching

Vertical splicing is to connect two tables by row, that is, expand the table by row. Vertical concatenation can be achieved using the concat() function in the pandas library.

example

import pandas as pd

# 创建两个表格
df1 = pd.DataFrame({'A': ['A0', 'A1', 'A2', 'A3'],
                    'B': ['B0', 'B1', 'B2', 'B3'],
                    'C': ['C0', 'C1', 'C2', 'C3'],
                    'D': ['D0', 'D1', 'D2', 'D3']})

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

# 将两个表格纵向拼接
result = pd.concat([df1, df2], axis=0)

print(result)

Output result:

    A   B   C   D
0  A0  B0  C0  D0
1  A1  B1  C1  D1
2  A2  B2  C2  D2
3  A3  B3  C3  D3
0  A4  B4  C4  D4
1  A5  B5  C5  D5
2  A6  B6  C6  D6
3  A7  B7  C7  D7