How do you reverse an array without using built-in methods?

Question

Accepted Answer

Reverse an array of strings without using methods

Create two pointers, one at the start and one at the end of the array
Swap the elements at the two pointers and move them towards the center until they meet
Example: ['apple', 'banana', 'cherry'] -> ['cherry', 'banana', 'apple']

Accepted Answer

def reverse_array(arr):
    # Initialize two pointers
    left = 0
    right = len(arr) - 1
    
    # Swap elements until the pointers meet
    while left < right:
        # Swap elements at the left and right pointers
        arr[left], arr[right] = arr[right], arr[left]
        # Move the pointers towards the center
        left += 1
        right -= 1
    
    return arr

# Example input
input_array = ['apple', 'banana', 'cherry']

# Reverse the array
result = reverse_array(input_array)

# Print the result
print("Reversed array:", result)

Accepted Answer

arr = [10, 2, 8, 1, 3]

l, r = 0, len(arr) - 1

while l < r:
    arr[l], arr[r] = arr[r], arr[l]
    l += 1
    r -= 1

print(arr)