# Problem 6: Reverse a List (without using reverse())

Hey everyone! 👋

Today, we're tackling a fundamental problem: **Reversing a List** manually.

## **The Problem**

The goal is to write a function that reverses a list without using the built-in `reverse()` method or slicing with `[::-1]`. This is a great exercise to understand how list indexing works.

**Example:**

* `reverse_list([1, 2, 3, 4])` should return `[4, 3, 2, 1]`
    

## **The Solution**

Here is the Python implementation using a loop:

```python
def reverse_list(lst):
    """
    Reverses a list by iterating backwards.
    """
    reversed_list = []
    # Loop from the last index to 0
    for i in range(len(lst)-1, -1, -1):
        reversed_list.append(lst[i])

    return reversed_list

# Test case
print(reverse_list([1, 2, 3, 4]))
# Output: [4, 3, 2, 1]
```

## **Code Breakdown**

Let's walk through the code line by line:

1. `def reverse_list(lst):`
    
    * Defines a function named `reverse_list` that takes one parameter `lst` (a list).
        
2. `reversed_list = []`
    
    * Creates an empty list called `reversed_list` to store the reversed elements.
        
3. `for i in range(len(lst)-1, -1, -1):`
    
    * Starts a loop that will iterate from the last index of the list to the first (0).
        
    * `len(lst)-1` is the starting index (last element).
        
    * `-1` (the second argument) is the stopping index (stops before -1, so 0 is included).
        
    * `-1` (The third argument) is the step (counts backwards).
        
4. `reversed_list.append(lst[i])`
    
    * For each iteration, it takes the element at index `i` from the original list and appends it to `reversed_list`.
        
5. `return reversed_list`
    
    * Returns the new list with elements in reverse order.
        

### **Example Walkthrough with** `[1, 2, 3, 4]`

1. `i` starts at 3 (value 4), appends 4 to `reversed_list`.
    
2. `i` becomes 2 (value 3), appends 3.
    
3. `i` becomes 1 (value 2), appends 2.
    
4. `i` becomes 0 (value 1), appends 1.
    
5. Returns `[4, 3, 2, 1]`.
    

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Happy coding! 💻