Lambda Functions

Lambda Functions: Anonymous Functions

What is a Lambda Function?

A lambda function is a small, anonymous function defined using the lambda keyword. Unlike regular functions defined with the def keyword, lambda functions don’t have a name. They are typically used for short, simple operations.

Syntax

Python

lambda arguments: expression

• lambda: Keyword to indicate a lambda function.
• arguments: Optional parameters to the function.
• expression: The operation to be performed and returned.

Example

Python

add = lambda x, y: x + y
result = add(3, 4)
print(result)  # Output: 7

In this example:

• lambda x, y: x + y defines a lambda function that takes two arguments, x and y, and returns their sum.
• The function is assigned to the variable add.
• The add function is called with arguments 3 and 4, and the result is printed.

Key Points

• Lambda functions are typically used for short, one-line expressions.
• They are often used with higher-order functions like map, filter, and reduce.
• They can be assigned to variables or passed as arguments to other functions.
• While lambda functions can be used for simple operations, complex logic is better handled by regular functions.

Common Use Cases

• Sorting:Pythonmy_list = [(1, 'a'), (3, 'c'), (2, 'b')] sorted_list = sorted(my_list, key=lambda x: x[0]) print(sorted_list) # Output: [(1, 'a'), (2, 'b'), (3, 'c')
• Filtering:Pythonnumbers = [1, 2, 3, 4, 5] even_numbers = list(filter(lambda x: x % 2 == 0, numbers)) print(even_numbers) # Output: [2, 4]
• Mapping:Pythonnumbers = [1, 2, 3, 4, 5] squared_numbers = list(map(lambda x: x * x, numbers)) print(squared_numbers) # Output: [1, 4, 9, 16, 25]

Limitations

• Lambda functions are limited to a single expression.
• For complex logic, regular functions are preferred.

By understanding lambda functions, you can write more concise and expressive code, especially when working with higher-order functions.

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