Sorting List of Tuples using Key and Lambda Function in Python
- Posted by Admin
- on August 23, 2022
- in Python
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Here we will be sorting a list of tuples having first names and last names of cricket players by their last names.
This is the list of tuples:
players = [("Sachin", "Tendulkar"),
("Sunil","Gavaskar"),
("Kapil","Dev"),
("MS","Dhoni"),
("Saurav","Ganguly")]The desired output is should be like
[(‘Kapil’, ‘Dev’), (‘MS’, ‘Dhoni’), (‘Saurav’, ‘Ganguly’), (‘Sunil’, ‘Gavaskar’), (‘Sachin’, ‘Tendulkar’)]
Solution
# Input List of Tuples
players = [("Sachin", "Tendulkar"),
("Sunil","Gavaskar"),
("Kapil","Dev"),
("MS","Dhoni"),
("Saurav","Ganguly")]
# Using Lambda Function sorting can be applied to the last name
players.sort(key=lambda x: x[1])
# Print after sorting
print(players)
# Output
# [('Kapil', 'Dev'), ('MS', 'Dhoni'), ('Saurav', 'Ganguly'), ('Sunil', 'Gavaskar'), ('Sachin', 'Tendulkar')]If we have two players with the same last name and want the first name also to be sorted after the last name, then the below solution works for you.
Use of a custom key using the lambda function, we can achieve this.
# Input List of Tuples
players = [("Sachin", "Tendulkar"),
("Ramesh", "Tendulkar"),
("Sunil","Gavaskar"),
("Kapil","Dev"),
("MS","Dhoni"),
("Saurav","Ganguly")]
# Custom Key
custom_key = lambda x: (x[1], x[0])
# Using Lambda Function sorting can be applied to the last name
print(sorted(players, key=custom_key))
# Output
# [('Kapil', 'Dev'), ('MS', 'Dhoni'), ('Saurav', 'Ganguly'),
# ('Sunil', 'Gavaskar'), ('Ramesh', 'Tendulkar'), ('Sachin', 'Tendulkar')]