MNIST数据集是机器学习领域中非常经典的一个数据集，由60000个训练样本和10000个测试样本组成，每个样本都是一张28 * 28像素的灰度手写数字图片。(The MNIST data set is a very classic data set in the field of machine learning. It consists of 60,000 training samples and 10,000 test samples. Each sample is a 28 * 28 p