SlideShare a Scribd company logo

Python Functions

•Download as PPTX, PDF•
•
M
Mohammed Sikander

Python functions allow for reusable code through defining functions, passing arguments, returning values, and setting scopes. Functions can take positional or keyword arguments, as well as variable length arguments. Default arguments allow functions to specify default values for optional parameters. Functions are objects that can be assigned to variables and referenced later.

1 of 21
Python Functions ● Define functions ● Passing arguments to Function ● Return a value from function ● Scope of Objects ● Default arguments ● Positional and keyword arguments ● Variable length arguments
Functions  Piece of reusable code  Solves particular task  Call function instead of writing code yourself
Built-in Functions
Syntax of Function Mohammed Sikander 4
Defining a function
Function Call  Once we have defined a function, we can call it from another function, program or even the Python prompt.  To call a function we simply type the function name with appropriate parameters. Calling the Function my_function()
Square function:Take one arguments and prints its square
Square function:Take one arguments and returns its square
Function returning multiple value
Scope and Lifetime of variables  Scope of a variable is the portion of a program where the variable is recognized.  Parameters and variables defined inside a function is not visible from outside. Hence, they have a local scope.  Lifetime of a variable is the period throughout which the variable exits in the memory. The lifetime of variables inside a function is as long as the function executes.  They are destroyed once we return from the function. Hence, a function does not remember the value of a variable from its previous calls.
Python Functions
Python Functions
Python Functions
Default Arguments  Function arguments can have default values in Python.  We can provide a default value to an argument by using the assignment operator (=).
Default Arguments  In this function, the parameter amount does not have a default value and is required (mandatory) during a call.  On the other hand, the parameter discountPercentage has a default value of 0. So, it is optional during a call.  If a value is provided, it will overwrite the default value.  Any number of arguments in a function can have a default value.
Default Arguments  Once we have a default argument, all the arguments to its right must also have default values.  SyntaxError: non-default argument follows default argument
Keyword Arguments
 Positional argument cannot follow keyword argument
Variable number of arguments
Functions as Objects ● Although functions are created differently from normal variables, functions are just like any other kind of value. ● They can be assigned and reassigned to variables, and later referenced by those names.
Python Functions

More Related Content

Python Functions

  • 1. Python Functions ● Define functions ● Passing arguments to Function ● Return a value from function ● Scope of Objects ● Default arguments ● Positional and keyword arguments ● Variable length arguments
  • 2. Functions  Piece of reusable code  Solves particular task  Call function instead of writing code yourself
  • 6. Function Call  Once we have defined a function, we can call it from another function, program or even the Python prompt.  To call a function we simply type the function name with appropriate parameters. Calling the Function my_function()
  • 7. Square function:Take one arguments and prints its square
  • 8. Square function:Take one arguments and returns its square
  • 10. Scope and Lifetime of variables  Scope of a variable is the portion of a program where the variable is recognized.  Parameters and variables defined inside a function is not visible from outside. Hence, they have a local scope.  Lifetime of a variable is the period throughout which the variable exits in the memory. The lifetime of variables inside a function is as long as the function executes.  They are destroyed once we return from the function. Hence, a function does not remember the value of a variable from its previous calls.
  • 14. Default Arguments  Function arguments can have default values in Python.  We can provide a default value to an argument by using the assignment operator (=).
  • 15. Default Arguments  In this function, the parameter amount does not have a default value and is required (mandatory) during a call.  On the other hand, the parameter discountPercentage has a default value of 0. So, it is optional during a call.  If a value is provided, it will overwrite the default value.  Any number of arguments in a function can have a default value.
  • 16. Default Arguments  Once we have a default argument, all the arguments to its right must also have default values.  SyntaxError: non-default argument follows default argument
  • 18.  Positional argument cannot follow keyword argument
  • 19. Variable number of arguments
  • 20. Functions as Objects ● Although functions are created differently from normal variables, functions are just like any other kind of value. ● They can be assigned and reassigned to variables, and later referenced by those names.