Python | Ways to sort a zipped list by values

Sorting a zipped list in Python refers to arranging pairs of elements, typically tuples, based on their values. This allows us to reorder the list according to the second item in each pair, while keeping the key-value relationship intact. In this article we'll explore ways to sort a zipped list by values.

Using sorted() with operator.itemgetter()

operator.itemgetter() is a fast way to sort a zipped list by values. It efficiently retrieves specific elements from tuples, making it ideal for sorting large datasets.

Example:

import operator
a = ['akshat', 'Manjeet', 'nikhil']
b = [3, 2, 1]
zipped = zip(a,b)

# Converting to list
zipped = list(zipped)

# Using sorted and operator
res = sorted(zipped, key = operator.itemgetter(1))
print(str(res))

[('akshat', 3), ('Manjeet', 2), ('nikhil', 1)]

Explanation:

• This code zips lists a and b into pairs.
• It sorts the pairs by the second element .
• Result is a list sorted by values in b in ascending order.

Let's understand more ways to sort a zipped list by values .

Using sorted () with lambda

Lambda functions provide a flexible way to sort a zipped list by values, allowing custom sorting logic. This method is simple and useful for quick sorting tasks in Python.

Example:

a = ['geeks', 'for', 'Geeks']
b= [3, 2, 1]

# Zipping the lists
zipped = zip(a,b)

# Converting to list
zipped = list(zipped)

# Sorting by second element
res = sorted(zipped, key=lambda x: x[1],)
print(res)

[('Geeks', 1), ('for', 2), ('geeks', 3)]

Explanation:

• This code zips lists a and b and sorts the pairs by the second element in ascending order using lambda function.

The sort() method sorts a zipped list in place, which means it modifies the list directly without creating a new one. While this is efficient for smaller datasets, it may be slower than using sorted() with operator.itemgetter() for larger datasets.

Example:

a = ['geeks','for','Geeks']
b = [3, 2, 1]

# Zipping the lists
zipped = zip(a, b)

# Converting to list
zipped = list(zipped)

# Sorting in-place by second element
zipped.sort(key=lambda x: x[1])
print(zipped)

[('Geeks', 1), ('for', 2), ('geeks', 3)]

Explanation:

• This code zips lists a and b into pairs of corresponding elements.
• It sorts the pairs in-place by the second element in ascending order using lambda function.