Lambda Functions

Let's Learn Lambda Functions!

Lambda functions are small anonymous functions. A lambda function can take any number of arguments, but can only have one expression. They are used for simple tasks that can be done in a single line. Their major use is inside map, filter and reduce functions which take a callback function as an argument and defining a function and naming it makes code more complicated.

In this simulation, you are going to learn the use of lambda functions and why they should be used over a normal function definition.

You are given a program which illustrates the use of a lambda function. You are required to give it input and observe the output.

Run the program

>>> f = lambda x : >>> a = input("Enter a

number or string

: ")
Enter a number or string:
>>> try: a = int(a) except: pass >>> print(f(a))

Submit

Output is:

Observations

x*2

Applications of Lambda Functions

Drag and drop the options to the blanks to complete the program to perform a task using map, filter and reduce functions with lambda functions as parameters.

The goal of this function will be to take a list of numbers and use the map, filter and reduce functions to return the sum of all even squares of the numbers in the list.

              Input = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
              
              Output:
              
              [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
              
              [4, 16, 36, 64, 100]
              
              220

Complete the program

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] squares = list(map(

, numbers)) filtered = list(filter(

, squares)) sum = reduce(

, filtered) print(squares, filtered, sum, sep='\n')

lambda x : x*x

lambda x : x%2

lambda x : not x%2

lambda x,y : x+y

lambda x : x+x

lambda x,y : x*y

The same application without lambda functions

Complete the experiment first!