defdata_iter(batch_size,features,labels):
????num_examples=len(features)
????indices=list(range(num_examples))
????random.shuffle(indices)? ?
???for i in range(0,num_examples,batch_size):
????????????j=nd.array(indices[i:min(i+batch_size,num_examples)])
????????????yield features.take(j),labels.take(j)????????????# take函數(shù)根據(jù)索引返回對應元素
