keras加载mnist数据集

from keras.datasets import mnist
(train_images,train_labels),(test_images,test_labels)=mnist.load_data()

此处会报 SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed 错误

通过下面命令解决

> cd "/Applications/Python 3.7/"
> sudo "./Install Certificates.command"

 载入并训练数据集

from keras.datasets import mnist

(train_images,train_labels),(test_images,test_labels)=mnist.load_data()

from keras import models
from keras import layers
network = models.Sequential()

#准备网络
network.add(layers.Dense(512,activation='relu',input_shape=(28*28,)))
network.add(layers.Dense(10,activation='softmax'))
network.compile(optimizer='rmsprop',loss='categorical_crossentropy',metrics=['accuracy'])

#准备图像数据
train_images = train_images.reshape((60000,28*28))
train_images = train_images.astype('float32') /255

test_images = test_images.reshape((10000,28*28))
test_images = test_images.astype('float32') /255

#准备标签
from keras.utils import to_categorical
train_labels = to_categorical(train_labels)
test_labels = to_categorical(test_labels)

#训练数据
network.fit(train_images,train_labels,epochs=5,batch_size=128)

# 测试性能
test_loss,test_acc = network.evaluate(test_images,test_labels)
print('test_acc:',test_acc)