如何将长格式(可能是稀疏)的DataFrame转换为多维数组或NamedArray

import pandas as pd
import numpy as np

# 创建一个长格式的DataFrame
df = pd.DataFrame({
    'index': [0, 0, 0, 1, 1, 1, 2, 2, 2],
    'column': ['A', 'B', 'C', 'A', 'B', 'C', 'A', 'B', 'C'],
    'value': [1, 2, 3, 4, 5, 6, 7, 8, 9]
})

# 将长格式的DataFrame转换为多维数组
array = df.pivot(index='index', columns='column', values='value').values

# 将长格式的DataFrame转换为NamedArray
named_array = np.array([tuple(x) for x in df[['value', 'column']].values],
                       dtype=[('value', int), ('column', 'U10')]).view(np.recarray)

print("多维数组:")
print(array)

print("NamedArray:")
print(named_array)