title: What does the 1 in torch.Size([64, 1, 28, 28]) mean when I check a tensor shape?
body: <p>I'm following <a href="https://towardsdatascience.com/handwritten-digit-mnist-pytorch-977b5338e627" rel="nofollow noreferrer">this tutorial on towardsdatascience.com</a> because I wanted to try the MNIST dataset using Pytorch since I've already done it using keras.</p>
  <p>So in Step 2, knowing the dataset better, they print the trainloader's shape and it returns <code>torch.Size([64, 1, 28, 28])</code>. I understand  that 64 is the number of images in that loader and that each one is a 28x28 image but what does the 1 mean exactly?</p>