Delete many elements of list (python)

Question

I have a list L.

I can delete element i by doing:

del L[i]

But what if I have a set of non contiguous indexes to delete?

Answer 1

You can use numpy.delete as follows:

import numpy as np
a = ['a', 'l', 3.14, 42, 'u']
I = [1, 3, 4]
np.delete(a, I).tolist()
# Returns: ['a', '3.14']

If you don't mind ending up with a numpy array at the end, you can leave out the .tolist(). You should see some pretty major speed improvements, too, making this a more scalable solution. I haven't benchmarked it, but numpy operations are compiled code written in either C or Fortran.