2.6 Python Language Fundamentals: Functions in Python
Functions in Python are reusable blocks of code that perform specific tasks within a program. They are fundamental to Python programming as they allow developers to organize and reuse code efficiently. In this module, we will explore the fundamentals of Python functions and how they can be used in backend development with Lambda and API Gateway.
Definition of Functions
In Python, a function is defined using the 'def' keyword, followed by the function name and parentheses (). Inside the parentheses, you can include any parameters that the function must accept. The syntax is as follows:
def function_name(parameter1, parameter2):
# function code
For example, a function that adds two numbers can be defined as follows:
def add(number1, number2):
sum = number1 + number2
return sum
The 'return' keyword is used to specify the result that the function should return. If no return value is specified, the function returns None.
Function Call
Once a function is defined, it can be called anywhere in your program. To call a function, you use the function name followed by parentheses and any arguments that the function requires. For example:
result = add(5, 3) print(result) # Output: 8
In this example, the 'add' function is called with arguments 5 and 3, and the result is stored in the 'result' variable.
Parameters and Arguments
The terms parameter and argument are often used interchangeably, but in Python they have different meanings. A parameter is a variable listed in parentheses in the function definition, while an argument is the value that is sent to the function when it is called. For example, in the 'add' function definition, 'number1' and 'number2' are parameters, while in the function call example, 5 and 3 are arguments.
Lambda functions
Python also supports lambda functions, which are small anonymous functions defined with the 'lambda' keyword. Lambda functions can be used where object functions are required. They are synthetically restricted to a single expression. For example, a lambda function that adds two numbers could be defined as follows:
add = lambda number1, number2: number1 + number2 print(add(5, 3)) # Output: 8
Lambda functions are particularly useful when working with higher-order functions that accept other functions as arguments.
Conclusion
Functions in Python are a powerful tool that allows developers to organize and reuse code efficiently. They are fundamental for programming in Python and are essential for developing backend applications with Lambda and API Gateway. By mastering the concepts of function definition, function calling, parameters and arguments, and lambda functions, you will be well prepared to write clean, efficient Python code.
