How can I import the MNIST dataset that has been manually downloaded?

Question

I have been experimenting with a Keras example, which needs to import MNIST data

from keras.datasets import mnist
import numpy as np
(x_train, _), (x_test, _) =          


        

Answer 1

Keras file is located into a new path in Google Cloud Storage (Before it was in AWS S3):

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

When using:

tf.keras.datasets.mnist.load_data()

You can pass a path parameter.

load_data() will call get_file() which takes as parameter fname, if path is a full path and file exists, it will not be downloaded.

Example:

# gsutil cp gs://tensorflow/tf-keras-datasets/mnist.npz /tmp/data/mnist.npz
# python3
>>> import tensorflow as tf
>>> path = '/tmp/data/mnist.npz'
>>> (train_images, train_labels), (test_images, test_labels) = tf.keras.datasets.mnist.load_data(path)
>>> len(train_images)
>>> 60000

Answer 2

1. Download file https://s3.amazonaws.com/img-datasets/mnist.npz
2. Move mnist.npz to .keras/datasets/ directory

3. Load data

   import keras
   from keras.datasets import mnist
   
   (X_train, y_train), (X_test, y_test) = mnist.load_data()
   

Answer 3

Well, the keras.datasets.mnist file is really short. You can manually simulate the same action, that is:

1. Download a dataset from https://s3.amazonaws.com/img-datasets/mnist.pkl.gz

2. .

   import gzip
   f = gzip.open('mnist.pkl.gz', 'rb')
   if sys.version_info < (3,):
       data = cPickle.load(f)
   else:
       data = cPickle.load(f, encoding='bytes')
   f.close()
   (x_train, _), (x_test, _) = data
   

Answer 4

You do not need additional code for that but can tell load_data to load a local version in the first place:

1. You can download the file https://s3.amazonaws.com/img-datasets/mnist.npz from another computer with proper (proxy) access (taken from https://github.com/keras-team/keras/blob/master/keras/datasets/mnist.py),
2. copy it to the the directory ~/.keras/datasets/ (on Linux and macOS)
3. and run load_data(path='mnist.npz') with the right file name