MNIST+SVM手写数字分类

一、参考链接：
1.https://www.cnblogs.com/yaowuyangwei521/p/9975714.html
2.https://www.cnblogs.com/pinard/p/6126077.html
3.降低维度之后分类，并可视化结果
https://zodiac911.github.io/blog/mnist-analysis.html#%E9%99%8D%E7%BB%B4%E6%96%B9%E6%B3%95%E6%AF%94%E8%BE%83

二、MNIST获取部分数字数据（比如仅仅取4和9的图像及对应标签）
train_filter = np.where((y_train == 9) | (y_train == 4))
test_filter = np.where((y_pred == 9) | (y_pred == 4))

X_train, Y_train = X_train[train_filter], y_train[train_filter]
X_test, Y_test = x_test[test_filter], y_pred[test_filter]
来源：https://stackoverflow.com/questions/51202181/how-do-i-select-only-a-specific-digit-from-the-mnist-dataset-provided-by-keras