Creating Concise Anonymous Functions with Lambda
Lambda functions are anonymous functions used to express simple operations without a function name.
The term anonymous means that the function you write doesn’t have a name.
Unlike functions defined with the def keyword, keyword, lambda functions use the lambda keyword, enabling a short and concise expression.
lambda arguments: expression
In this structure, arguments represent inputs to the function, and expression is the operation performed on these inputs.
Here’s a simple example of a lambda function:
# Lambda function that returns the sum of two numbers
add = lambda x, y: x + y
# 'add' is a variable pointing to the lambda function
print(add(3, 5)) # Output: 8
# Lambda function that returns the square of a given number
square = lambda x: x * x
print(square(4))
# Output: 16
Beyond simple arithmetic operations like those above, you can create more complex lambda functions using conditions.
# Lambda function to check if a given number is even or odd
is_even = lambda x: 'Even' if x % 2 == 0 else 'Odd'
print(is_even(3))
# Output: Odd
In the code above, the is_even lambda function uses the condition 'Even' if x % 2 == 0 to return 'Even' if the given number x is divisible by 0, and 'Odd' otherwise.
When to Use Lambda Functions?
Lambda functions have the following advantages over regular functions defined with the def keyword:
-
Concise Function Definition: You can define simple functions in one line, keeping the code clean and easy to read.
-
Use as Function Arguments: They're ideal for passing as arguments to other functions, enhancing code flexibility and reusability.
# Example of using lambda with the filter() function
numbers = [1, 2, 3, 4, 5]
# Create a new list by filtering even numbers from the list 'numbers'
even_numbers = filter(lambda x: x % 2 == 0, numbers)
print(list(even_numbers))
# Output: [2, 4]
Want to learn more?
Join CodeFriends Plus membership or enroll in a course to start your journey.