Swapping variables with tuples

What this problem practises

Tuples are immutable containers that may themselves hold mutable objects, and it is the comma — not the parentheses — that builds one. Any unpacking where the counts disagree raises ValueError.

This is an output-prediction problem: read the snippet carefully and write down exactly what it prints before anything runs. These questions are interview staples because they test whether you know the language rules, or merely recognise their syntax.

Difficulty: medium — expect to hold two interacting rules in your head at once, such as a boundary combined with a mutation.

The challenge

The code runs in PyDebug’s in-browser compiler. Open the problem, run the snippet, watch the exact error or output, and keep iterating until it is right. Signed-in solves count toward XP and your daily streak.

The snippet

The interactive editor pre-fills exactly this code — read it, then submit your prediction:

a = 5
b = 10
a, b = b, a
print(a, b)

x, y, z = 1, 2, 3
x, y, z = z, x, y
print(x, y, z)

More tuples problems

• Tuple immutability easy
• ValueError: too many values to unpack easy
• ValueError: too many values to unpack easy

Keep going

• Output-prediction strategies — how to predict tricky snippets without running them.
• Browse every tuples problem in this topic.
• Common Python errors and what they actually mean, plus the Python glossary for any term used on this page.