By the end of this lesson, you can:

• Unpack a known number of sequence elements into multiple variables.
• Swap values in one assignment without a temporary variable.
• Capture an unknown-length middle section with starred unpacking.
• Unpack pairs and nested (number, record) values while iterating.

In Python, unpacking assigns elements from a sequence to several variables at once:

service, region = ("api", "eu")

The number of targets must match the number of elements, unless one target is starred. A star collects the remaining elements into a list:

first, *middle, last = [2, 4, 6, 8]

Here, middle is [4, 6]. It can also be empty when the input contains just two items. Only one starred target is allowed in a single unpacking assignment.

Multiple assignment also makes swapping simple: a, b = b, a evaluates the right side before assigning the names.

Unpacking works naturally with for loops: for name, score in pairs: gives useful names to the two parts of every pair. You can also unpack a pair inside enumerate() using for number, (name, score) in enumerate(pairs, start=1):. This is a good fit when the record itself contains several fields but you also need its position.

1. Give names to two values

host, port = ("db.internal", 5432)
print(f"Connect: {host}:{port}")

Output:

Connect: db.internal:5432

The two tuple elements are assigned to the two names, in order.

2. Swap without an extra variable

front = "blue"
back = "orange"
front, back = back, front
print(f"Front: {front}, back: {back}")

Output:

Front: orange, back: blue

Both old values are captured before either name changes.

3. Capture the unknown-length middle

measurements = [10, 12, 14, 16, 20]
first, *middle, last = measurements
print(first)
print(middle)
print(last)

Output:

10
[12, 14, 16]
20

The starred target always receives a list, even when it has no values.

4. Unpack records while numbering them

checks = [("lint", True), ("tests", False)]
for number, (name, passed) in enumerate(checks, start=1):
    print(f"{number}. {name}: {passed}")

Output:

1. lint: True
2. tests: False

The outer pair holds (number, record); the inner pair splits the record into (name, passed).

• Without a starred target, unpacking too many or too few elements raises ValueError.
• The starred target produces a list even when the original sequence is a tuple.
• A normal assignment with one name does not unpack the record into fields.
• enumerate(pairs) returns (index, pair), not three separate values.