Python Functions

Functions

Defining a Function

• A function is a block of code that can be executed multiple times from different parts of a program
• Functions are defined using the def keyword followed by the function name and parameters in parentheses
• The function body is indented below the definition

Function Syntax

• def function_name(parameters):
• # function body

Function Parameters

• Parameters are values passed to a function when it's called
• Parameters can be assigned default values using the = operator
• def greet(name = 'World'): print('Hello, ' + name + '!')

Function Return

• The return statement is used to exit a function and return a value
• If no value is specified, the function returns None
• def add(a, b): return a + b

Function Calls

• Functions are called by using the function name followed by parentheses containing the arguments
• greet('John') or result = add(2, 3)

Lambda Functions

• Lambda functions are small, anonymous functions that can be defined inline
• lambda keyword is used to define a lambda function
• add = lambda a, b: a + b

Function Scope

• Variables defined inside a function are local to that function and cannot be accessed outside
• Global variables can be accessed inside a function, but it's not recommended to modify them
• global keyword can be used to modify a global variable inside a function

Function Arguments

• Arguments can be passed to a function in three ways:
  • Positional arguments: func(a, b, c)
  • Keyword arguments: func(a=1, b=2, c=3)
  • Default arguments: func(a, b, c=3)

Variable Number of Arguments

• The * operator can be used to pass a variable number of arguments to a function
• The ** operator can be used to pass a variable number of keyword arguments to a function
• def func(*args, **kwargs):

Functions

Defining a Function

• A function is a reusable block of code that can be executed multiple times from different parts of a program.
• The def keyword is used to define a function, followed by the function name and parameters in parentheses.
• The function body is indented below the definition.

Function Syntax

• The basic syntax for a function is def function_name(parameters): followed by the function body.
• The function body is indented below the definition.

Function Parameters

• Parameters are values passed to a function when it's called, and can be assigned default values using the = operator.
• Parameters can be assigned default values, which are used if no value is provided when the function is called.

Function Return

• The return statement is used to exit a function and return a value to the caller.
• If no value is specified, the function returns None by default.

Function Calls

• Functions are called by using the function name followed by parentheses containing the arguments.
• Arguments can be passed to a function in different ways, including positional, keyword, and default arguments.

Lambda Functions

• Lambda functions are small, anonymous functions that can be defined inline using the lambda keyword.
• Lambda functions are used to define small, one-time-use functions.

Function Scope

• Variables defined inside a function are local to that function and cannot be accessed outside.
• Global variables can be accessed inside a function, but it's not recommended to modify them.
• The global keyword can be used to modify a global variable inside a function.

Function Arguments

• Arguments can be passed to a function in three ways:
  • Positional arguments: func(a, b, c)
  • Keyword arguments: func(a=1, b=2, c=3)
  • Default arguments: func(a, b, c=3)

Variable Number of Arguments

• The * operator can be used to pass a variable number of arguments to a function.
• The ** operator can be used to pass a variable number of keyword arguments to a function.
• The *args and **kwargs syntax can be used to pass a variable number of arguments and keyword arguments to a function.