python - Insert element into numpy array

Question

Lists have a very simple method to insert elements:

a = [1,2,3,4]
a.insert(2,66)
print a
[1, 2, 66, 3, 4]

For a numpy array I could do:

a = np.asarray([1,2,3,4])
a_l = a.tolist()
a_l.insert(2,66)
a = np.asarray(a_l)
print a
[1 2 66 3 4]

but this is very convoluted.

Is there an insert equivalent for numpy arrays?

Answer 1

You can use numpy.insert, though unlike list.insert it returns a new array because arrays in NumPy have fixed size.

>>> import numpy as np
>>> a = np.asarray([1,2,3,4])
>>> np.insert(a, 2, 66)
array([ 1,  2, 66,  3,  4])