无法使用Keras和Sklearn将字符串列转换为类别矩阵

import pandas as pd
from sklearn.preprocessing import LabelEncoder
from sklearn.preprocessing import OneHotEncoder
from keras.utils import to_categorical

# 假设有一个包含字符串列的DataFrame
data = pd.DataFrame({'category': ['A', 'B', 'C', 'A', 'B', 'C']})

# 将字符串列转换为数值表示
label_encoder = LabelEncoder()
data['category_encoded'] = label_encoder.fit_transform(data['category'])

# 将数值表示转换为类别矩阵
onehot_encoder = OneHotEncoder(sparse=False)
category_matrix = onehot_encoder.fit_transform(data['category_encoded'].values.reshape(-1, 1))

# 使用Keras的to_categorical函数进行类别矩阵转换
category_matrix_keras = to_categorical(data['category_encoded'])

print(category_matrix)
print(category_matrix_keras)