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Introduction to Python Lambda

Python Lambda​

A lambda function, also known as an anonymous function, is a way to create small, one-line functions without explicitly defining them using the def keyword.

Lambda functions are typically used for simple tasks or as arguments to higher-order functions.

The syntax for a lambda function is as follows:

lambda arguments: expression

Here's an example that demonstrates the usage of a lambda function to calculate the square of a number:

square = lambda x: x ** 2

result = square(5)
print(result)  # Output: 25

In this example:

  • The lambda function takes a single argument x and returns the square of x using the expression x ** 2.
  • The lambda function is assigned to the variable square, and then it is called with the value 5 as the argument.

Lambda functions can also take multiple arguments:

add = lambda x, y: x + y

result = add(3, 4)
print(result)  # Output: 7

In this example:

  • The lambda function takes two arguments x and y and returns their sum using the expression x + y.

They are commonly used in combination with higher-order functions like map(), filter(), and reduce().

You can use a lambda function with map() to apply a transformation to each element of a list.

As an example:

numbers = [1, 2, 3, 4, 5]
squared_numbers = list(map(lambda x: x ** 2, numbers))
print(squared_numbers)  # Output: [1, 4, 9, 16, 25]

In this example:

  • The lambda function is used as the first argument to map().
  • It takes each element x from the numbers list and returns its square.
  • The resulting squared numbers are collected into a new list using list().