In Python, a lambda function is a small anonymous function that can have any number of arguments but can only have one expression. It is created using the lambda keyword, followed by a comma-separated list of arguments, a colon, and an expression. Here is the general syntax of a lambda function:
lambda arguments: expression
Lambda functions are often used as a way to create small, one-line functions that can be passed as arguments to other functions. They are particularly useful when you need to create a function on the fly without defining a named function.
Here’s an example of a lambda function that squares a number:
square = lambda x: x ** 2
You can then call the lambda function like a regular function:
result = square(5) print(result) # Output: 25
Lambda functions can also be used as arguments for other functions. For example, the
map() function takes a function and an iterable as arguments and applies the function to each element of the iterable. Here’s an example of using a lambda function with
map() to square each element of a list:
numbers = [1, 2, 3, 4, 5] squares = map(lambda x: x ** 2, numbers) print(list(squares)) # Output: [1, 4, 9, 16, 25]
Lambda functions are a powerful tool in Python for creating small, anonymous functions that can be used in a variety of contexts. However, they should be used judiciously, as they can make code harder to read and understand if overused.