# How to Convert Tuple of Tuples to List of Lists in Python?

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💬 Question: Given a tuple of tuples such as `((1, 2), (3, 4))`. How to convert it to a list of lists such as `[[1, 2], [3, 4]]`?

If you’re in a hurry, here’s the most Pythonic way to convert a nested tuple to a nested list:

The list comprehension statement `[list(x) for x in tuples]` converts each tuple in `tuples` to a list and stores the results in a list of lists.

But there’s more to it! Studying the different methods to achieve the same goal will make you a better coder.

## Method 1: List Comprehension + list()

The recommended way to convert a tuple of tuples to a list of lists is using list comprehension in combination with the built-in `list()` function like so: `[list(x) for x in tuples]`.

Here’s a concrete example:

```tuples = ((1, 2), (3, 4), (5, 6))
lists = [list(x) for x in tuples]

print(lists)
# [[1, 2], [3, 4], [5, 6]]
```

Try It Yourself:

This approach is simple and effective. List comprehension defines how to convert each tuple (`x` in the example) to a new list element. As each list element is a new list, you use the constructor `list(x)` to create a new list from the tuple `x`.

### Example Three Elements per Tuple

If you have three elements per tuple, you can use the same approach with the conversion:

```tuples = ((1, 2, 1), (3, 4, 3), (5, 6, 5))
lists = [list(x) for x in tuples]
print(lists)
```

You can see the execution flow in the following interactive visualization (just click the “Next” button to see what’s happening in the code):

### Example Varying Number of Tuple Elements

And if you have a varying number of elements per tuple, this approach still works beautifully:

```tuples = ((1,), (3, 3), (5, 6, 5))
lists = [list(x) for x in tuples]

print(lists)
# [, [3, 3], [5, 6, 5]]```

You see that an approach with list comprehension is the best way to convert a tuple of tuples to a list of lists.

But are there any alternatives?

## Method 2: Use Asterisk and List Comprehension

A variant of the recommended way to convert a tuple of tuples to a list of lists is using list comprehension in combination with the unpacking asterisk operator `*` like so: `[[*x] for x in tuples]`.

Here’s an example:

```tuples = ((1,), (3, 3), (5, 6, 5))
lists = [[*x] for x in tuples]

print(lists)
# [, [3, 3], [5, 6, 5]]```

The unpacking operator `[*x]` takes all tuple elements from `x` and “unpacks” them in the outer list container `[...]`. For example, the expression `[*(5, 6, 5)]` yields the list `[5, 6, 5]`.

Let’s have a look at a completely different approach to solve this problem:

## Method 3: Map Function + list()

Use the map function that applies a specified function on each element of an iterable.

💡Side Note: Guido van Rossum, the creator of Python, didn’t like the `map()` function as it’s less readable and less efficient than the list comprehension version (Method 1 in this tutorial). You can read about a detailed discussion on how exactly he argued on my blog article.

So, without further ado, here’s how you can convert a tuple of tuples into a list ot lists using the `map()` function:

```tuples = ((1,), (2, 3, 4), (5, 6, 7, 8))
lists = list(map(list, tuples))

print(lists)
# [, [2, 3, 4], [5, 6, 7, 8]]
```

Try it yourself:

Video tutorial on the `map()` function:

The first argument of the `map()` function is the `list` function name.

This `list()` function converts each element on the given iterable `tuples` (the second argument) into a list.

The result of the `map()` function is an iterable too, so you need to convert it to a list before printing it to the shell because the default string representation of an iterable is not human-readable.

## Method 4: Simple For Loop with append() and list()

To convert a tuple of tuples to a list of lists, a simple three-liner is to first initialize an empty “outer” list and store it in a variable. Then iterate over all tuples using a simple `for` loop and convert each separately to a list and append each result to the outer list variable using the `list.append()` builtin method in the loop body.

The following example does exactly that:

```tuples = ((1,), (2, 3, 4), (5, 6, 7, 8))

lists = []
for t in tuples:
lists.append(list(t))

print(lists)
# [, [2, 3, 4], [5, 6, 7, 8]]
```

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