如何将dataframe列的值放入2d矩阵？

import pandas as pd
import numpy as np

data = {'A': [1, 2, 3], 'B': [4, 5, 6], 'C': [7, 8, 9]}
df = pd.DataFrame(data)

matrix = np.zeros((df.shape[0], df.shape[1]))

for i, col in enumerate(df.columns):
    matrix[:, i] = df[col].values

import pandas as pd
import numpy as np

data = {'A': [1, 2, 3], 'B': [4, 5, 6], 'C': [7, 8, 9]}
df = pd.DataFrame(data)

matrix = np.zeros((df.shape[0], df.shape[1]))

for i, col in enumerate(df.columns):
    matrix[:, i] = df[col].values

print(matrix)