Stack Overflow

numpy

• numpy: Efficiently avoid 0s when taking log(matrix)

Answer by John Zwinck

We can use masked arrays for this:

log_x = np.ma.log(x).filled(0)

matplotlib

• Prevent matplotlib statefulness

Answer by Joe Kington

Normally, when you call plt.figure(), it:

1. Creates the figure object that’s returned
2. Creates a FigureManager for that figure using the appropriate backend
3. The figure manager creates a FigureCanvas, gui window (as needed), and NavigationToolbar2 (zoom buttons, etc)
4. The figure manager instance is then added to _pylab_helpers.Gcf’s list of figures.

It’s this last step that we want to bypass.