A `while` loop isn't only good for counting! Similar to how we saw `for` loops working with lists, we can use `while` loops to iterate through a list as well. Let's return to our ingredient list: ```py ingredients = ["milk", "sugar", "vanilla extract", "dough", "chocolate"] ``` We know that `while` loops require some form of a variable to track the condition of the loop to start and stop. Take some time to think about what we would use to track whether we need to start/stop the loop if we want to iterate through `ingredients` and print every element.

Click here to find out!

We know that a list has a predetermined length. If we use the length of the list as the basis for how long our while loop needs to run, we can iterate the exact length of the list.

We can use the [built-in Python `len()` function](https://docs.python.org/3/library/functions.html#len) to accomplish this: ```py # Length would be equal to 5 length = len(ingredients) ```

We can then use this `length` in addition to another variable to construct the `while` loop: ```py length = len(ingredients) index = 0 while index < length: print(ingredients[index]) index += 1 ``` Let's break this down: ```py # Length will be 5 in this case length = len(ingredients) ```

Explanation

As mentioned, we need a way to know how many times we need our loop to iterate based on the size of the collection.

This comes in the form of our length variable which stores the value of the length of the list.

```py # Index starts at zero index = 0 ```

Explanation

We still need an additional variable that will be used to compare against our length.

```py while index < length: ```

Explanation

In our while loop conditional, we will compare the index variable to the length of our list stored inside of the length variable.

On the first iteration, we will be comparing the equivalent of `0 < 5` which will evaluate to True, and start the execution of our loop body.

```py # The first iteration will print ingredients[0] print(ingredients[index]) ```

Explanation

Inside of our loop body, we can use the index variable to access our ingredients list and print the value at the current iteration.

Since our index starts at zero, our first iteration will print the value of the element at the zeroth index of our ingredients list, then the next iteration will print the value of the element at the first index, and so on.

```py # Increment index to access the next element in ingredients # Each iteration gets closer to making the conditional no longer true index += 1 ```

Explanation

 
On each iteration of our while loop, we need to also increment the value of index to make sure our loop can stop once the index value is no longer smaller than the length value.

This increment also helps us access the next value of the ingredients list on the next iteration.

Our final output would be: ```bash milk sugar vanilla extract dough chocolate ``` Let's use a `while` loop to iterate through some lists!