You are given two arrays `arr1` and `arr2`, where `arr2` always contains integers.
Write the function `find_array(arr1, arr2)` such that:
For `arr1 = ['a', 'a', 'a', 'a', 'a']`, `arr2 = [2, 4]`
`find_array returns ['a', 'a']`
For `arr1 = [0, 1, 5, 2, 1, 8, 9, 1, 5]`, `arr2 = [1, 4, 7]`
`find_array returns [1, 1, 1]`
For `arr1 = [0, 3, 4]`, `arr2 = [2, 6]`
`find_array returns [4]`
For `arr1=["a","b","c","d"]` , `arr2=[2,2,2]`,
`find_array returns ["c","c","c"]`
For `arr1=["a","b","c","d"]`, `arr2=[3,0,2]`
`find_array returns ["d","a","c"]`
If either `arr1` or `arr2` is empty, you should return an empty arr (empty list in python,
empty vector in c++). Note for c++ use std::vector arr1, arr2.
def find_array(arr1, arr2):
    return [arr1[i] for i in arr2 if i <= len(arr1)]
def find_array(arr1, arr2):
    return [arr1[i] for i in arr2 if i <= len(arr1)]