AttributeError: 'Tensor' object has no attribute 'numpy'

添加：tf.enable_eager_execution()，開啓即時模式

A = tf.constant([[1., 2.], [3., 4.]])
B = tf.constant([[5., 6.], [7., 8.]])
tf.enable_eager_execution()
print(A.shape)      # 輸出(2, 2)，即矩陣的長和寬均爲2
print(A.dtype)      # 輸出<dtype: 'float32'>
print(A.numpy())    # 輸出[[1. 2.]
                    #      [3. 4.]]