Anaconda安装Keras:

conda install keras

安装完成:

在Jupyter Notebook中新建并执行代码:

import keras
from keras.datasets import mnist # 从keras中导入mnist数据集
from keras.models import Sequential # 导入序贯模型
from keras.layers import Dense # 导入全连接层
from keras.optimizers import SGD # 导入优化函数

(x_train, y_train), (x_test, y_test) = mnist.load_data() # 加载mnist数据集

因为众所周知的原因,下载墙外的文件超时报错,参考 https://www.cnblogs.com/shinny/p/9283372.html 进行修改;

重复执行,报错:“TabError: inconsistent use of tabs and spaces in indentation”

参照 https://blog.csdn.net/qq_41096996/article/details/85947560 进行修改:

执行成功!

继续执行如下代码:

print(x_train.shape,y_train.shape)
#(60000, 28, 28) (60000,)

print(x_test.shape,y_test.shape)
#(10000, 28, 28) (10000,)

继续执行:

import matplotlib.pyplot as plt # 导入可视化的包
im = plt.imshow(x_train[0],cmap='gray')

继续执行:

plt.show()
y_train[0]

继续执行:

x_train = x_train.reshape(60000,784) # 将图片摊平,变成向量
x_test = x_test.reshape(10000,784) # 对测试集进行同样的处理
print(x_train.shape)
#(60000, 784)
print(x_test.shape)
#(10000, 784)

继续执行:

x_train[0]
#array([  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   3,  18,  18,  18,
       126, 136, 175,  26, 166, 255, 247, 127,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,  30,  36,  94, 154, 170, 253,
       253, 253, 253, 253, 225, 172, 253, 242, 195,  64,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,  49, 238, 253, 253, 253,
       253, 253, 253, 253, 253, 251,  93,  82,  82,  56,  39,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  18, 219, 253,
       253, 253, 253, 253, 198, 182, 247, 241,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
        80, 156, 107, 253, 253, 205,  11,   0,  43, 154,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,  14,   1, 154, 253,  90,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0, 139, 253, 190,   2,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,  11, 190, 253,  70,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  35,
       241, 225, 160, 108,   1,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,  81, 240, 253, 253, 119,  25,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,  45, 186, 253, 253, 150,  27,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,  16,  93, 252, 253, 187,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 249,
       253, 249,  64,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  46, 130,
       183, 253, 253, 207,   2,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  39, 148,
       229, 253, 253, 253, 250, 182,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  24, 114,
       221, 253, 253, 253, 253, 201,  78,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  23,  66,
       213, 253, 253, 253, 253, 198,  81,   2,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  18, 171,
       219, 253, 253, 253, 253, 195,  80,   9,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  55, 172,
       226, 253, 253, 253, 253, 244, 133,  11,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
       136, 253, 253, 253, 212, 135, 132,  16,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
         0,   0,   0,   0], dtype=uint8)

继续执行:

x_train = x_train / 255
x_test = x_test / 255
x_train[0]
#array([0.        , 0.        , 0.        , 0.        , 0.        ,
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       0.65098039, 1.        , 0.96862745, 0.49803922, 0.        ,
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       0.        , 0.11764706, 0.14117647, 0.36862745, 0.60392157,
       0.66666667, 0.99215686, 0.99215686, 0.99215686, 0.99215686,
       0.99215686, 0.88235294, 0.6745098 , 0.99215686, 0.94901961,
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       0.99215686, 0.74509804, 0.00784314, 0.        , 0.        ,
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       0.        , 0.1372549 , 0.94509804, 0.88235294, 0.62745098,
       0.42352941, 0.00392157, 0.        , 0.        , 0.        ,
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       0.99215686, 0.99215686, 0.78823529, 0.30588235, 0.        ,
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       0.        , 0.09019608, 0.25882353, 0.83529412, 0.99215686,
       0.99215686, 0.99215686, 0.99215686, 0.77647059, 0.31764706,
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       0.        , 0.        , 0.        , 0.        , 0.        ,
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       0.        , 0.        , 0.        , 0.        , 0.        ,
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       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        ])

继续执行:

y_train = keras.utils.to_categorical(y_train,10)
y_test = keras.utils.to_categorical(y_test,10)

继续执行:

model = Sequential() # 构建一个空的序贯模型
# 添加神经网络层
model.add(Dense(512,activation='relu',input_shape=(784,)))
model.add(Dense(256,activation='relu'))
model.add(Dense(10,activation='softmax'))
model.summary()

返回信息:

WARNING:tensorflow:From C:\3rd\Anaconda2\lib\site-packages\tensorflow\python\framework\op_def_library.py:263: colocate_with (from tensorflow.python.framework.ops) is deprecated and will be removed in a future version.
Instructions for updating:
Colocations handled automatically by placer.
_________________________________________________________________
Layer (type)                 Output Shape              Param #
=================================================================
dense_1 (Dense)              (None, 512)               401920
_________________________________________________________________
dense_2 (Dense)              (None, 256)               131328
_________________________________________________________________
dense_3 (Dense)              (None, 10)                2570
=================================================================
Total params: 535,818
Trainable params: 535,818
Non-trainable params: 0
_________________________________________________________________

继续执行:

model.compile(optimizer=SGD(),loss='categorical_crossentropy',metrics=['accuracy'])
model.fit(x_train,y_train,batch_size=64,epochs=5,validation_data=(x_test,y_test)) # 此处直接将测试集用作了验证集

返回正在执行信息:

执行结束信息:

WARNING:tensorflow:From C:\3rd\Anaconda2\lib\site-packages\tensorflow\python\ops\math_ops.py:3066: to_int32 (from tensorflow.python.ops.math_ops) is deprecated and will be removed in a future version.
Instructions for updating:
Use tf.cast instead.
Train on 60000 samples, validate on 10000 samples
Epoch 1/5
60000/60000 [==============================] - 7s 123us/step - loss: 0.7558 - acc: 0.8162 - val_loss: 0.3672 - val_acc: 0.8991
Epoch 2/5
60000/60000 [==============================] - 7s 112us/step - loss: 0.3356 - acc: 0.9068 - val_loss: 0.2871 - val_acc: 0.9204
Epoch 3/5
60000/60000 [==============================] - 7s 112us/step - loss: 0.2798 - acc: 0.9211 - val_loss: 0.2537 - val_acc: 0.9296
Epoch 4/5
60000/60000 [==============================] - 7s 117us/step - loss: 0.2468 - acc: 0.9302 - val_loss: 0.2313 - val_acc: 0.9332
Epoch 5/5
60000/60000 [==============================] - 7s 122us/step - loss: 0.2228 - acc: 0.9378 - val_loss: 0.2084 - val_acc: 0.9404
<keras.callbacks.History at 0x1dcaea054a8>

继续执行:

score = model.evaluate(x_test,y_test)
#10000/10000 [==============================] - 1s 53us/step

继续执行:

print("loss:",score[0])
#loss: 0.2084256855905056

继续执行:

print("accu:",score[1])
#accu: 0.9404

参考:

https://www.cnblogs.com/ncuhwxiong/p/9836648.html

https://www.cnblogs.com/shinny/p/9283372.html

https://blog.csdn.net/qq_41096996/article/details/85947560

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