Lambda Functions In Python
Hi there. In this Python programming post, I provide a quick overview of lambda functions. Lambda/anonymous functions are a neat way of defining Python functions with less lines of code.
If I wanted to add ten to a regular number with a regular Python function, I can define a function that takes a numeric input and returns ten plus that input. Then I would need a function call as follows.
def add_ten(x):
return x + 10
test_value = 7
print(add_ten(test_value))
17
With a lambda function, I can skip the def part of defining a function and simply do this.
add_ten = lambda x: x + 10
print(add_ten(7))
17
The numeric value of 7 in the add_ten(7) function call takes on the role of x.
Lambda Functions With Lists
If you have more than one numeric value for the input such as a list of numbers you would use the map() function along with a lambda function. With the map() function, the first argument is the function and the second argument is the list as the input.
test_list = [1, 10, -1, 2, 5, 7, 8]
print(list(map(add_ten, test_list)))
[11, 20, 9, 12, 15, 17, 18]
print(list(map(lambda x: x + 10, test_list)))
[11, 20, 9, 12, 15, 17, 18]
