# Python Lambda Functions

Lambda functions, also known as anonymous functions, are a powerful feature in Python that allow you to create small, inline functions without the need for a formal def statement. Lambda functions are concise and versatile, making them a valuable tool in your Python programming arsenal. In this article, we’ll explore Python’s Lambda functions in depth, providing real-world examples and their corresponding outputs for a hands-on learning experience. Lambda functions in Python are a valuable tool for writing concise and expressive code. They are versatile and can be used in various scenarios, such as sorting, filtering, and mapping data.

### What are Lambda Functions?

Lambda functions in Python are small, anonymous functions defined using the lambda keyword. They are often used for short, simple operations that can be expressed in a single line of code. The basic syntax of a lambda function is as follows:

lambda arguments: expression


Here, arguments represent the input parameters to the function, and expression is the operation performed on those arguments. Lambda functions can take multiple arguments but must consist of a single expression.

### Lambda Functions in Action

Let’s dive into some real-world examples to understand how lambda functions work:

#### Example 1: Sorting a List of Tuples

students = [('Alice', 95), ('Bob', 80), ('Charlie', 75)]
# Sort the list of tuples by the second element (marks)
sorted_students = sorted(students, key=lambda x: x[1])
print(sorted_students)

Output:

[('Charlie', 75), ('Bob', 80), ('Alice', 95)]


In this example, we used a lambda function as the key argument to the sorted() function. The lambda function lambda x: x[1] extracts the second element (marks) from each tuple, enabling us to sort the list of students based on their marks.

#### Example 2: Filtering Even Numbers

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
# Use a lambda function to filter even numbers
even_numbers = list(filter(lambda x: x % 2 == 0, numbers))
print(even_numbers)

Output:

[2, 4, 6, 8, 10]


In this example, we utilized a lambda function with the filter() function to extract even numbers from a list.

#### Example 3: Calculating Square Roots

import math
# Create a list of numbers
numbers = [9, 16, 25, 36, 49]
# Use a lambda function to calculate square roots
square_roots = list(map(lambda x: math.sqrt(x), numbers))
print(square_roots)

Output:

[3.0, 4.0, 5.0, 6.0, 7.0]


Here, we employed a lambda function with the map() function to calculate the square root of each number in a list.

### When to Use Lambda Functions

Lambda functions are particularly useful in situations where you need a simple, short function for a specific task. However, they are not a replacement for regular functions defined with def. Use lambda functions when the function logic is brief and can be expressed in a single line.

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