Convert Tuple to List | The Most Pythonic Way

Answer: The simplest, most straightforward, and most readable way to convert a tuple to a list is Python’s built-in list(tuple) function. You can pass any iterable (such as a tuple, another list, or a set) as an argument into this so-called constructor function and it returns a new list data structure that contains all elements of the iterable.

Converting a tuple to a list seems trivial, I know. But keep reading and I’ll show you surprising ways of handling this problem. I guarantee that you’ll learn a lot of valuable things from the 3-5 minutes you’ll spend reading this tutorial! 🙂

Problem: Given a tuple of elements. Create a new list with the same elements—thereby converting the tuple to a list.

Example: You have the following tuple.

t = (1, 2, 3)

You want to create a new list data structure that contains the same integer elements:

[1, 2, 3]

Let’s have a look at the different ways to convert a tuple to a list—and discuss which is the most Pythonic way in which circumstance.

You can get a quick overview in the following interactive code shell. Explanations for each method follow after that:

Exercise: Run the code. Skim over each method—which one do you like most? Do you understand each of them?

Let’s dive into the six methods.

Method 1: List Constructor

The simplest, most straightforward, and most readable way to convert a tuple to a list is Python’s built-in list(iterable) function. You can pass any iterable (such as a list, a tuple, or a set) as an argument into this so-called constructor function and it returns a new tuple data structure that contains all elements of the iterable.

Convert List to Tuple using tuple()

Here’s an example:

# Method 1: list() constructor
t = (1, 2, 3)
lst = list(t)
print(lst)
# [1, 2, 3]

This is the most Pythonic way if a flat conversion of a single tuple to a list is all you need. But what if you want to convert multiple tuples to a single list?

Method 2: Unpacking

There’s an alternative that works for one or more tuples to convert one or more tuples into a list. This method is equally efficient and it takes less characters than Method 1 (at the costs of readability for beginner coders). Sounds interesting? Let’s dive into unpacking and the asterisk operator!

The asterisk operator * is also called “star operator” and you can use it as a prefix on any tuple (or list). The operator will “unpack” all elements into an outer structure—for example, into an argument lists or into an enclosing container type such as a list or a tuple.

Here’s how it works to unpack all elements of a tuple into an enclosing list—thereby converting the original tuple to a new list.

# Method 2: Unpacking
t = (1, 2, 3)
lst = [*t]
print(lst)
# [1, 2, 3]

You unpack all elements in the tuple t into the outer structure [*t]. The strength of this approach is—despite being even conciser than the standard list(...) function—that you can unpack multiple values into it!

Method 3: Unpacking to Convert Multiple Tuples to a Single List

Let’s have a look at how you’d create a list from multiple tuples:

# Method 3: Unpacking Multiple Tuples
t1 = (1, 2, 3)
t2 = (4, 5, 6)
lst = [*t1, *t2]
print(lst)
# [1, 2, 3, 4, 5, 6]

The expression [*t1, *t2] unpacks all elements in tuples t1 and t2 into the outer list. This allows you to convert multiple tuples to a single list.

Method 4: Generator Expression to Convert Multiple Tuples to List

If you have multiple tuples stored in a list of lists (or list of tuples) and you want to convert them to a single list, you can use a short generator expression statement to go over all inner tuples and over all elements of each inner tuple. Then, you place each of those elements into the list structure:

# Method 4: Generator Expression
ts = ((1, 2), (3, 4), (5, 6, 7))
lst = [x for t in ts for x in t]
print(lst)
# [1, 2, 3, 4, 5, 6, 7]

This is the most Pythonic way to convert a list of tuples (or tuple of tuples) to a tuple. It’s short and efficient and readable. You don’t create any helper data structure that takes space in memory.

But what if you want to save a few more characters?

Method 5: Generator Expression + Unpacking

Okay, you shouldn’t do this last method using the asterisk operator—it’s unreadable—but I couldn’t help including it here:

# Method 5: Generator Expression + Unpacking
t = ((1, 2), (3, 4), (5, 6, 7))
lst = [*(x for t in ts for x in t)]
print(lst)
# [1, 2, 3, 4, 5, 6, 7]

Rather than using the list(...) function to convert the generator expression to a list, you use the [...] helper structure to indicate that it’s a list you want—and unpack all elements from the generator expression into the list. Sure, it’s not very readable—but you could see such a thing in practice (if pro coders want to show off their skills ;)).

Method 6: Simple For Loop

Let’s end this article by showing the simple thing—using a for loop. Doing simple things is an excellent idea in coding. And, while the problem is more elegantly solved in Method 1 (using the list() constructor), using a simple loop to fill an initially empty list is the default strategy.

# Method 6: Simple For Loop
t = (1, 2, 3, 4)
lst = []
for x in t:
    lst.append(x)
print(lst)
# [1, 2, 3, 4]

To understand how the code works, you can visualize its execution in the interactive memory visualizer:

Exercise: How often is the loop condition checked?

You will see such a simple conversion method in code bases of Python beginners and programmers who switch to Python coming from other programming languages such as Java or C++. It’s readable but it lacks conciseness.

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