Skip to main content

Python Unpack Tuple with Variable Length

banner-python

Tuple Unpacking with Variable Length in Python​

In Python, we can unpack a tuple with a variable length using star expressions (also known as extended unpacking). If the number of variables doesn’t match the number of values, it can raise a "too many values to unpack" exception.

1. Unpack a Tuple with Variable Length​

Star expressions, introduced in Python 3, allow us to assign parts of a tuple to variables while collecting the rest into a list using the * operator.

Example​

# Example tuple with a variable length
my_tuple = (1, 2, 3, 4, 5)

# Unpack the first two elements and collect the rest in another variable
first, second, *rest = my_tuple

# Print the results
print("First:", first)
print("Second:", second)
print("Rest:", rest)

Output:

First: 1  
Second: 2  
Rest: [3, 4, 5]

We can use the star expression at various positions in variable assignments to dynamically collect elements — at the beginning, middle, or end.

Another Example​

# Example tuple with a variable length
my_tuple = (1, 2, 3, 4, 5)

# Collect the first two elements, skip the third, and collect the rest
first, second, *skip, last = my_tuple

# Print the results
print("First:", first)
print("Second:", second)
print("Last:", last)
print("Skipped:", skip)

Output:

First: 1  
Second: 2  
Last: 5  
Skipped: [3, 4]

2. Unpack Tuple and Ignore Unwanted Values​

Sometimes, we may want to ignore specific elements in a tuple. In such cases, we can use the underscore (_) as a placeholder to discard values.

Example1​

# Example tuple with unwanted values
my_tuple = (1, 2, 3, 4, 5)

# Unpack the tuple and ignore unwanted values
first, _, third, _, _ = my_tuple

# Print the values you're interested in
print("First:", first)
print("Third:", third)

3. Error: Too Many Values to Unpack​

This error occurs when the number of variables on the left-hand side of the assignment doesn’t match the number of values in the tuple, and you're not using a star expression.

Problematic Example​

my_tuple = (1, 2, 3, 4, 5)

first, second, third = my_tuple  # ❌ Too many values

Error Output:

Traceback (most recent call last):
  File "<string>", line 3, in <module>
ValueError: too many values to unpack (expected 3)

✅ Tip: Always use *rest when you're unsure about the number of elements in the tuple or want to collect extras cleanly.

Happy Learning! 🎉