Retrieving training and test data

The MNIST dataset already comprises both training and test data. There are 60,000 data points of training data and 10,000 points of test data. If you do not have the data file locally at the '~/.keras/datasets/' + path, it can be downloaded at this location.

Each MNIST data point has:

• An image of a handwritten digit
• A corresponding label that is a number from 0-9 to help identify the image

The images will be called, and will be the input to our neural network, X; their corresponding labels are y.

We want our labels as one-hot vectors. One-hot vectors are vectors of many zeros and one. It's easiest to see this in an example. The number 0 is represented as [1, 0, 0, 0, 0, 0, 0, 0, 0, 0], and 4 is represented as [0, 0, 0, 0, 1, 0, 0, 0, 0, 0] as a one-hot vector.