Tuple unpacking lets you swap two variables without creating a third temporary variable. Python evaluates the right side before assigning the targets.
Understanding the Concept
In many languages, swapping values requires a temporary name. Python can express the operation as first_value, second_value = second_value, first_value. The values on the right are evaluated using the original bindings, then assigned to the left. The same principle works for other multiple assignments and is useful for reading tuple-based data.
When and Why You Would Use This
The example starts with two labels and exchanges them. This is a value swap, not a character-by-character modification of the strings.
Practical Example
first_label = "left"
second_label = "right"
first_label, second_label = second_label, first_label
print(first_label, second_label)Understanding the Example
The output is right left. Both right-hand values are obtained before Python rebinds the two names. There is no need to create a temporary variable manually.
Example Output
right leftTry It Yourself
Swap two numeric values and then swap them back. Print both states.
Common Beginner Mistakes
- Writing assignments one after another and overwriting the original value before using it.
- Thinking the swap modifies immutable string objects in place.
- Using tuple unpacking without matching the number of values and targets.
Key Takeaways
- Tuple unpacking supports concise simultaneous assignment.
- Python evaluates the entire right-hand side before rebinding the names.
- This makes swapping values simple and readable.