Google I/O adalah bungkusnya! Ikuti sesi TensorFlow Lihat sesi

Muat data NumPy

Lihat di TensorFlow.org Jalankan di Google Colab Lihat sumber di GitHub Unduh buku catatan

Tutorial ini memberikan contoh memuat data dari array NumPy ke dalam tf.data.Dataset .

Contoh ini memuat kumpulan data MNIST dari file .npz . Namun, sumber array NumPy tidak penting.

Mempersiapkan

import numpy as np
import tensorflow as tf

Muat dari file .npz

DATA_URL = 'https://storage.googleapis.com/tensorflow/tf-keras-datasets/mnist.npz'

path = tf.keras.utils.get_file('mnist.npz', DATA_URL)
with np.load(path) as data:
  train_examples = data['x_train']
  train_labels = data['y_train']
  test_examples = data['x_test']
  test_labels = data['y_test']

Muat array NumPy dengan tf.data.Dataset

Dengan asumsi Anda memiliki larik contoh dan larik label yang sesuai, teruskan kedua larik tersebut sebagai tuple ke tf.data.Dataset.from_tensor_slices untuk membuat tf.data.Dataset .

train_dataset = tf.data.Dataset.from_tensor_slices((train_examples, train_labels))
test_dataset = tf.data.Dataset.from_tensor_slices((test_examples, test_labels))

Gunakan kumpulan data

Acak dan kelompokkan kumpulan data

BATCH_SIZE = 64
SHUFFLE_BUFFER_SIZE = 100

train_dataset = train_dataset.shuffle(SHUFFLE_BUFFER_SIZE).batch(BATCH_SIZE)
test_dataset = test_dataset.batch(BATCH_SIZE)

Bangun dan latih model

model = tf.keras.Sequential([
    tf.keras.layers.Flatten(input_shape=(28, 28)),
    tf.keras.layers.Dense(128, activation='relu'),
    tf.keras.layers.Dense(10)
])

model.compile(optimizer=tf.keras.optimizers.RMSprop(),
              loss=tf.keras.losses.SparseCategoricalCrossentropy(from_logits=True),
              metrics=['sparse_categorical_accuracy'])
model.fit(train_dataset, epochs=10)
Epoch 1/10
938/938 [==============================] - 3s 2ms/step - loss: 3.5318 - sparse_categorical_accuracy: 0.8762
Epoch 2/10
938/938 [==============================] - 2s 2ms/step - loss: 0.5408 - sparse_categorical_accuracy: 0.9289
Epoch 3/10
938/938 [==============================] - 2s 2ms/step - loss: 0.3770 - sparse_categorical_accuracy: 0.9473
Epoch 4/10
938/938 [==============================] - 2s 2ms/step - loss: 0.3281 - sparse_categorical_accuracy: 0.9566
Epoch 5/10
938/938 [==============================] - 2s 2ms/step - loss: 0.2940 - sparse_categorical_accuracy: 0.9621
Epoch 6/10
938/938 [==============================] - 2s 2ms/step - loss: 0.2622 - sparse_categorical_accuracy: 0.9657
Epoch 7/10
938/938 [==============================] - 2s 2ms/step - loss: 0.2446 - sparse_categorical_accuracy: 0.9698
Epoch 8/10
938/938 [==============================] - 2s 2ms/step - loss: 0.2147 - sparse_categorical_accuracy: 0.9739
Epoch 9/10
938/938 [==============================] - 2s 2ms/step - loss: 0.1956 - sparse_categorical_accuracy: 0.9750
Epoch 10/10
938/938 [==============================] - 2s 2ms/step - loss: 0.1964 - sparse_categorical_accuracy: 0.9759
<keras.callbacks.History at 0x7fc7a80beb50>
model.evaluate(test_dataset)
157/157 [==============================] - 0s 2ms/step - loss: 0.7089 - sparse_categorical_accuracy: 0.9572
[0.7088937163352966, 0.9571999907493591]