【TensorFlow】“Hello World”

# 导包
import tensorflow as tf

# 加载数据集
(x_train, y_train), (x_test, y_test) = tf.keras.datasets.mnist.load_data()
# 数据归一化
x_train, x_test = x_train / 255.0, x_test / 255.0

# 构建模型
model = tf.keras.models.Sequential([
    tf.keras.layers.Flatten(input_shape=(28, 28)),
    tf.keras.layers.Dense(128, activation='relu'),
    tf.keras.layers.Dropout(0.2),
    tf.keras.layers.Dense(10, activation='softmax')
])

# 模型编译
model.compile(optimizer='adam',
              loss='sparse_categorical_crossentropy',
              metrics=['accuracy'])
# 模型训练
model.fit(x_train, y_train, epochs=5)
# 模型评估
model.evaluate(x_test, y_test, verbose=2)