Sample showing the power of slices and letting callers specify the output array for NumPy like ufuncs

run.txt

primesieve-python pstoll$ python testnumpy.py
straight into array: [ 2  3  5  7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71]
offset by 10: [ 0  0  0  0  0  0  0  0  0  0  2  3  5  7 11 13 17 19 23 29]
strided by 2: [ 2  0  3  0  5  0  7  0 11  0 13  0 17  0 19  0 23  0 29  0]

testnumpy.py

import primesieve as ps
import numpy as np

n = 10**6
a = np.zeros( (2*n,), dtype=np.uint64)

# store the primes into the array a starting at position 0
ps.generate_n_primes_numpy( n, out=a)
print("straight into array:", a[0:20])

# store the primes in 10 spots offset into the array a
a = np.zeros( (2*n,), dtype=np.uint64)
b = ps.generate_n_primes_numpy( n, out=a[10::])
print("offset by 10:", a[0:20])

# store the primes into every other location of array a
a = np.zeros( (2*n,), dtype=np.uint64)
b = ps.generate_n_primes_numpy( n, out=a[::2])
print("strided by 2:", a[0:20])