Semicolon in plot: Video part #36

[kaustubhharapanahalli]

Hello,

In the plot_prediction function, what is the reason for using the semi-colon? Usually, in Python, we don't prefer using semi-colon right, so I am confused as to why that is present there.

I see the same in the blog post as well. Could you please clarify this?

These are the links to refer to what I am talking about:
Video: https://youtu.be/Z_ikDlimN6A?t=17450
Blog: https://www.learnpytorch.io/01_pytorch_workflow/#split-data-into-training-and-test-sets

Thanks

[mrdbourke]

Hey @kaustubhharapanahalli,

The semicolon hides Matplotlib outputs afterwards (only shows the plot).

Try with/without in a notebook and you'll see what I mean.

With:

def plot_predictions(train_data=X_train, 
                     train_labels=y_train, 
                     test_data=X_test, 
                     test_labels=y_test, 
                     predictions=None):
  """
  Plots training data, test data and compares predictions.
  """
  plt.figure(figsize=(10, 7))

  # Plot training data in blue
  plt.scatter(train_data, train_labels, c="b", s=4, label="Training data")
  
  # Plot test data in green
  plt.scatter(test_data, test_labels, c="g", s=4, label="Testing data")

  if predictions is not None:
    # Plot the predictions in red (predictions were made on the test data)
    plt.scatter(test_data, predictions, c="r", s=4, label="Predictions")

  # Show the legend
  plt.legend(prop={"size": 14});

plot_predictions();

Without:

def plot_predictions(train_data=X_train, 
                     train_labels=y_train, 
                     test_data=X_test, 
                     test_labels=y_test, 
                     predictions=None):
  """
  Plots training data, test data and compares predictions.
  """
  plt.figure(figsize=(10, 7))

  # Plot training data in blue
  plt.scatter(train_data, train_labels, c="b", s=4, label="Training data")
  
  # Plot test data in green
  plt.scatter(test_data, test_labels, c="g", s=4, label="Testing data")

  if predictions is not None:
    # Plot the predictions in red (predictions were made on the test data)
    plt.scatter(test_data, predictions, c="r", s=4, label="Predictions")

  # Show the legend
  plt.legend(prop={"size": 14})

plot_predictions()

[mrdbourke]

Update: I just tried this is Google Colab and it seems to do the same thing either way 🤔

Feel free to use it/not use it - it shouldn't cause harm :)

[kaustubhharapanahalli]

Oh cool! That makes sense, but I also observed what you mentioned in your second comment. So I was a bit confused about why we are using the semicolon. I assume that was a feature in the previous versions of matplotlib.