when does python delete variables?

Question

I know that python has an automatic garbage collector and so it should automatically delete variables when there are no more reference to them.

My impression is tha

Answer 1

Write stuff you want to clear from memory in separate functions. In your example, you can do

  def xdef(z):
    x = f(z) # x is a np.array and contains a lot of data 
    x0 = x[0]

  def funz(z):
    xdef(z)
    y = f(z + 1) # y is a np.array and contains a lot of data
    y0 = y[0]  

    return y[0], x[0] 

This will cause an exception