Lambda functions are a powerful feature in Python that allow you to create small anonymous functions at runtime. They are particularly useful for short operations that can be defined in a single line of code. In this article, we’ll explore three diverse examples of lambda functions that will help you understand their utility in various contexts.
In many programming tasks, you’ll find yourself needing to sort data based on specific criteria. Lambda functions are perfect for this, especially when working with lists of tuples.
## List of tuples containing names and ages
people = [('Alice', 30), ('Bob', 25), ('Charlie', 35), ('David', 20)]
## Sorting the list by age using a lambda function
sorted_people = sorted(people, key=lambda person: person[1])
print(sorted_people)
This code snippet sorts the list of tuples by the second element, which is the age, using a lambda function. The output will be:
[('David', 20), ('Bob', 25), ('Alice', 30), ('Charlie', 35)]
You can modify the key in the lambda function to sort by different criteria, such as sorting by name by changing person[1] to person[0].
Filtering data is a common requirement in programming. Lambda functions work beautifully with the filter() function to create new lists based on specific conditions.
## List of numbers
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
## Filtering even numbers using a lambda function
even_numbers = list(filter(lambda x: x % 2 == 0, numbers))
print(even_numbers)
In this example, the lambda function checks if a number is even and filters the original list accordingly. The output will be:
[2, 4, 6, 8, 10]
You can easily modify the condition in the lambda function to filter for odd numbers or any other criteria you need.
Using lambda functions with the map() function can help you transform data efficiently. In this example, we’ll use a lambda function to square each number in a list.
## List of numbers
numbers = [1, 2, 3, 4, 5]
## Squaring each number using a lambda function
squared_numbers = list(map(lambda x: x ** 2, numbers))
print(squared_numbers)
This code uses a lambda function to square each number in the list. The output will be:
[1, 4, 9, 16, 25]
You can modify the expression in the lambda function to perform other mathematical operations, such as cubing the numbers by changing x ** 2 to x ** 3.
These examples of lambda functions in Python demonstrate their versatility and efficiency in handling common programming tasks, from sorting and filtering to transforming data. By incorporating lambda functions into your coding practices, you can write cleaner, more concise code.