Python Zip Function

Python `zip()` Tutorial#

The zip() function in Python combines multiple iterables (lists, tuples, dictionaries, etc.) element-wise into tuples.

It is commonly used for:

✅ Pairing elements from multiple lists ✅ Iterating over multiple lists simultaneously ✅ Unzipping (extracting back original lists) ✅ Transforming a Transport Matrix

Summary of `zip()` Usage#

Use Case	Code Example
Pair elements	`zip(list1, list2)`
Loop over pairs	`for a, b in zip(list1, list2):`
Unzip data	`zip(*zipped_data)`
Handle different lengths	`itertools`.`zip_longest(list1, list2, fillvalue='?')`
Sort together	`sorted(zip(scores, names))`
Create a dictionary	`dict(zip(keys, values))`
Extract transport matrix columns	`list(zip(*matrix))`

1️⃣ Basic Usage of `zip()`#

🟢 Combining Two Lists

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list1 = [1, 2, 3]
list2 = ['a', 'b', 'c']

zipped = zip(list1, list2)
print(list(zipped))
# Output: [(1, 'a'), (2, 'b'), (3, 'c')]

✅ Pairs elements from both lists into tuples.

2️⃣ Iterating Over `zip()`#

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names = ["Alice", "Bob", "Charlie"]
scores = [85, 90, 88]

for name, score in zip(names, scores):
    print(f"{name} scored {score}")

Output:

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Alice scored 85
Bob scored 90
Charlie scored 88

✅ Iterates through paired elements from two lists.

3️⃣ Using `zip(*iterable)` to Unzip Data#

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zipped_data = [(1, 'a'), (2, 'b'), (3, 'c')]
num, char = zip(*zipped_data)

print(num)   # Output: (1, 2, 3)
print(char)  # Output: ('a', 'b', 'c')

✅ Extracts back original lists using zip(*).

4️⃣ `zip()` with Different Length Lists#

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list1 = [1, 2, 3]
list2 = ['a', 'b']

print(list(zip(list1, list2)))
# Output: [(1, 'a'), (2, 'b')]  (Stops at shortest list)

✅ Stops at the shortest iterable to avoid IndexError.

🔹 If you need to fill missing values, use itertools.zip_longest()

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from itertools import zip_longest
print(list(zip_longest(list1, list2, fillvalue='?')))
# Output: [(1, 'a'), (2, 'b'), (3, '?')]

5️⃣ Sorting with `zip()`#

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names = ["Alice", "Bob", "Charlie"]
scores = [85, 90, 88]

sorted_data = sorted(zip(scores, names), reverse=True)
print(sorted_data)
# Output: [(90, 'Bob'), (88, 'Charlie'), (85, 'Alice')]

✅ Sorts names based on scores using zip().

6️⃣ Creating a Dictionary Using `zip()`#

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keys = ['name', 'age', 'city']
values = ['Alice', 25, 'NYC']

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

✅ Efficiently converts two lists into a dictionary.

7️⃣ Using `zip()` in Transport Matrix#

The zip() function can be used to transpose a transport matrix, making it easier to access columns instead of rows.

Example: Transport Matrix#

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cost_matrix = [
    [8, 6, 10],  # Factory X -> Store A, B, C
    [9, 12, 7]   # Factory Y -> Store A, B, C
]

# Transpose the matrix using zip()
transposed_matrix = list(zip(*cost_matrix))

# Display the transposed transport matrix
for column in transposed_matrix:
    print(column)

Output:#

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(8, 9)
(6, 12)
(10, 7)

✅ zip(*cost_matrix) converts rows into columns, making store-wise access easier.

Python zip() Tutorial#

Summary of zip() Usage#

1️⃣ Basic Usage of zip()#

2️⃣ Iterating Over zip()#

3️⃣ Using zip(*iterable) to Unzip Data#

4️⃣ zip() with Different Length Lists#

5️⃣ Sorting with zip()#

6️⃣ Creating a Dictionary Using zip()#

7️⃣ Using zip() in Transport Matrix#