zip()

zip(*iterables, strict=False)

The zip() function takes multiple iterables and returns an iterator of tuples. Each tuple contains the corresponding elements from each iterable. This is useful for parallel iteration, creating dictionaries, and processing related data together.

Syntax

zip(*iterables, strict=False)

Parameters

Parameter	Type	Default	Description
*iterables	iterables	—	Two or more iterables to combine. Can be lists, tuples, strings, or any iterable.
strict	bool	False	If True, raises ValueError if the iterables have different lengths. Available in Python 3.10+.

Examples

Basic parallel iteration

names = ["Alice", "Bob", "Charlie"]
ages = [25, 30, 35]

for name, age in zip(names, ages):
    print(f"{name} is {age} years old")
# Alice is 25 years old
# Bob is 30 years old
# Charlie is 35 years old

Creating a dictionary

keys = ["name", "age", "city"]
values = ["Alice", 25, "London"]

person = dict(zip(keys, values))
print(person)
# {'name': 'Alice', 'age': 25, 'city': 'London'}

Using strict=True (Python 3.10+)

list1 = [1, 2, 3]
list2 = [4, 5]

# Without strict (stops at shortest)
result = list(zip(list1, list2))
print(result)
# [(1, 4), (2, 5)]

# With strict=True (raises ValueError)
try:
    result = list(zip(list1, list2, strict=True))
except ValueError as e:
    print(f"Error: {e}")
# Error: zip() argument 2 is shorter

Common Patterns

Converting two lists to a dict

columns = ["id", "name", "score"]
rows = [1, 2, 3], ["Alice", "Bob", "Charlie"], [95, 87, 91]

data = [dict(zip(columns, row)) for row in zip(*rows)]
print(data)
# [{'id': 1, 'name': 'Alice', 'score': 95}, {'id': 2, 'name': 'Bob', 'score': 87}, {'id': 3, 'name': 'Charlie', 'score': 91}]

Unzipping with the unpacking operator

pairs = [(1, 4), (2, 5), (3, 6)]

firsts, seconds = zip(*pairs)
print(firsts)
# (1, 2, 3)
print(seconds)
# (4, 5, 6)

Iterating over multiple sequences

x_coords = [1, 2, 3, 4]
y_coords = [10, 20, 30, 40]

points = list(zip(x_coords, y_coords))
print(points)
# [(1, 10), (2, 20), (3, 30), (4, 40)]

When zip() Stops

By default, zip() stops when the shortest iterable is exhausted. If you need all elements from all iterables, use itertools.zip_longest() from the standard library.

See Also

• built-in::enumerate — iterate with indices
• built-in::map — apply a function to elements