如何将Dataframe的每3行合并为1行(3列)

import pandas as pd

# 创建示例 DataFrame
data = {
    'A': [1, 2, 3, 4, 5, 6, 7, 8, 9]
}
df = pd.DataFrame(data)
print("Original DataFrame:")
print(df)

Original DataFrame:
   A
0  1
1  2
2  3
3  4
4  5
5  6
6  7
7  8
8  9

import numpy as np

# 将 DataFrame 转换为 NumPy 数组
array = df.values

# 确保行数是3的倍数，如果不是，可以填充NaN或其他值
if len(array) % 3 != 0:
    padding = 3 - len(array) % 3
    array = np.append(array, [np.nan] * padding).reshape(-1, 1)

# 重塑数组
reshaped_array = array.reshape(-1, 3)

# 转换回 DataFrame
df_reshaped = pd.DataFrame(reshaped_array, columns=['A', 'B', 'C'])
print("\nReshaped DataFrame:")
print(df_reshaped)

Reshaped DataFrame:
     A    B    C
0  1.0  2.0  3.0
1  4.0  5.0  6.0
2  7.0  8.0  9.0