In Python, a function is a block of code that is reusable and can be called multiple times. Functions help to organize and structure code by breaking it down into smaller, more manageable chunks. Functions can take input in the form of parameters and return output in the form of a return value.
To define a function in Python, you use the "def" keyword followed by the function name and a set of parentheses that may include parameters. The code block within the function is indented and begins with a colon. For example:
def greet(name): print("Hello, " + name + "!")
To call a function, you simply use the function name followed by a set of parentheses that may include any required arguments. For example:
Functions can also return values using the return statement. For example:
def add(a, b): return a + b result = add(3, 4) print(result)
Functions can have default argument values, which means that the arguments don't have to be passed while calling the function if they have default values. For example:
def greet(name, greeting="Hello"): print(greeting + ", " + name + "!") greet("Jeremiah") # Output: "Hello, Jeremiah!" greet("Jeremiah", "Hey") # Output: "Hi, Jeremiah!"
Functions can also take a variable number of arguments by using args and *kwargs. args allows the function to take a variable number of non-keyworded arguments and *kwargs allows a variable number of keyworded arguments.
Finally, Python has Anonymous functions or lambda functions which are small, one-time use functions that can be defined without a name using the lambda keyword.
add = lambda x, y: x + y result = add(3, 4) print(result)
All in all, I hope this brief introduction will give you an idea of the power and use of functions and how you can use them to write cleaner, better code.