Empty an existing NumPy array

Question

Now I have an numpy array X with certain column names, format and length. How can I set all the values to 0 (or empty) in this array, without deleting the format/names etc.?

Answer 1

Use numpy.ndarray.fill:

>>> import numpy as np
>>> a = np.arange(10)
>>> a
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> a.fill(0)
>>> a
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0])

Answer 2

You can use slicing:

>>> a = np.array([[1,2],[3,4]])
>>> a[:] = 0
>>> a
array([[0, 0],
       [0, 0]])