How do I implement binary search in Python?

How do I implement binary search in Python?

To implement binary search in Python, you can use a recursive or iterative approach. Which one would you prefer?

I think I prefer the iterative approach.

Great choice! Here's a simple iterative implementation:

def binary_search(arr, target):
    left, right = 0, len(arr) - 1
    while left <= right:
        mid = left + (right - left) // 2
        if arr[mid] == target:
            return mid
        elif arr[mid] < target:
            left = mid + 1
        else:
            right = mid - 1
    return -1

This function returns the index of the target if found, or -1 if not.

What if the array is not sorted?

Binary search requires a sorted array. If your array isn't sorted, you'll need to sort it first using a sorting algorithm like quicksort or mergesort.

Can you show me how to sort an array in Python?