Programming Essentials Python - User Defined Functions - Usage of Lambda Functions

Key Concepts Explanation

Lambda Functions

Lambda functions are anonymous functions in Python that are defined using the lambda keyword. These functions are used for creating small, one-time use functions without defining a proper function using def. Lambda functions are typically used when invoking functions that take other functions as arguments, such as filter, map, and sorted.

Filter

The filter function in Python is used to filter elements from an iterable based on a certain condition. It takes two arguments - a function that defines the condition and an iterable to be filtered. The function should return True for elements that should be included in the output.

Example:

males = filter(
    lambda user: user.split(',')[4] == 'Male',
    users
)
list(males)

Map

The map function in Python is used to apply a specific function to each element in an iterable. It takes two arguments - a function to apply to each element and an iterable. The function can be a lambda function or a regular function.

Example:

user_ips = map(
    lambda user: (int(user.split(',')[0]), user.split(',')[-1]),
    users
)
list(user_ips)

Sorted

The sorted function in Python is used to sort elements in an iterable. It takes the iterable to be sorted and an optional key argument that specifies a function to customize the sorting process. The key function is applied to each element for sorting.

Example:

sort_by_gender_and_id = sorted(
    users, 
    key=lambda user: (user.split(',')[4], int(user.split(',')[0]))
)
sort_by_gender_and_id

Hands-On Tasks

  1. Filter out males from the list of users and display the filtered list.
  2. Map the user IDs and IP addresses from the list of users and display the result.
  3. Sort the list of users based on gender and ID, then display the sorted list.

Conclusion

In this article, we learned about lambda functions in Python, specifically how they can be used with functions like filter, map, and sorted to manipulate and process data. By practicing the examples provided, readers can gain a better understanding of how lambda functions work and how they can be used effectively in Python programming. Remember to experiment with different functions and data sets to deepen your understanding of lambda functions and data manipulation. Happy coding!

Usage of Lambda Functions

![Video Placeholder: Provide Link Here](Video Explanation of Lambda Functions)

Watch the video tutorial here