Problem Statement

Select certain elements from an Array into a new Array in a generic way.

To demonstrate, select all even numbers from an Array. As an option, give a second solution which filters destructively, by modifying the original Array rather than creating a new Array.

Let's start with the solution:

a[] = [ 1 2 3 4 5 6 7 8 9 ]
for i = 1 to len a[]
  if a[i] mod 2 = 0
    b[] &= a[i]
  .
.
print b[]