Working With Function || Notes || Sumita Arora || Class 12 || Computer science || Information practices


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Working With Function



Function: - A function is a subprogram that act on data and often return a value.

 

Python function types:-

 

1 = Built in function: - These are pre-define function and always available for use. You have used some of them like - len (), type (), int (), input () etc.

 

2 = Function defined in modules: - These functions are pre-defined in particular modules and can only be used when the corresponding module is imported.

For example: - If we want to find the square root of any number then we have import math module then call the function - sqrt ()

 

3 = User defined functions: - These are define by the programmer. As programmer you can create your own function.

 

 

Defining function in python:-

Look figure carefully --

 




 

Function header: - The first line of the function definition that beings with keyword Def and ends with a colon (:), specifies the name of the function and its parameters.

 

Parameters: - Variables that are listed within the parentheses of a function header.

 

Function body: - The block of statement/indented - statement beneath function header that defines the action performed by the function.

 

Indentation: - The blank space in the beginning of statement within a block. All statements within same block have same indentation.

 

Flow of execution: - The flow of execution refers to the order in which statement are executed during a program run.




For example: -

def calcSum (x,y):

        s = x + y

        return s

num1 = float (input ("Enter the first number: "))

num2 = float (input("Enter the second number : "))

sum = calSum (num1,num2)

print("Sum of two given number is ",sum)

 

 

 

Argument: - The values being passed through a function call statement are called argument (or actual parameters or actual argument).

For example:-

def calcSum ( x , y ):

        s = x + y

        return s

 

print (calcSum ( 2 , 3 ))

a = 5

b = 6

print (calcSum ( a , b ))

d = 10

print (calcSum ( 9 , d ))

·         Here a , b , d , 2 , 3 , 9 are “arguments” which is used in call function.

 

Parameters: - The values received in the function definition header are called parameter (or formal parameters or formal arguments).

For example: -

def calcSum ( x , y ):

        :

·         Here x , y are “parameters”

 

Passing parameters:-

 

Python support three types of formal arguments/parameters:

 

1:- Positional argument (required arguments): - When the functions call statement must match the number and order of arguments as define in the functions definition this is called the position argument matching.

For example:-

def check (a,b,c):

       :

Then possible functions call for this can be:-

 

check ( x , y , z ) # 3 values( all variables) passed

 

check ( 2 , x , y ) # 3 values ( literal + variables ) passed

 

check ( 2 , 3 , 4 ) # 3 values ( all literal ) passed

 

Thus through such functions calls -

• The argument must be provided for all parameters (required)

• The values of argument are matched with parameters, position (order) wise (positional)

 

2:- Default arguments: - A parameter having defined value in the function header is known as a default parameter.

For example:-

def interest( principal , time , rate = 10 ) :

                :

If:-

si = interest ( 5400,2 ) #third argument missing

 

So the parameter principal get value 5400, time get 2 and since the third argument rate is missing, so default value 0.10 is used for rate.

 

If:-

si = interest ( 6100 ,3 ,0.15 ) # no argument missing

 

So the parameter principal get value 6100, time get 3 and the parameter rate gets value 0.15.

 

 

• That means the default values (values assigned in function header) are considered only if no value is provided for that parameter in the function call statement.

• Default argument are useful in situations where some parameters always have same value.

 

You can understand more by seeing below examples:-

 

def interest ( prin , time , rate = 0.10) # legal

 

def interest ( prin , time = 2 , rate) # illegal ( default parameter before required parameter )

 

def interest ( prin = 2000 ,time = 2 ,rate) # illegal

# (same reason as above)

 

def interest ( prin , time = 2 , rate = 0.10 ) # legal

 

def interest ( prin = 2000 , time = 2 , rate = 0.10) # legal

 

 

Some advantages of the default parameters are listed below:-

• They can be used to add new parameters to the existing functions.

• They can used to combine similar function into one.

 

3:- Keyword (or named ) arguments:-

Keyword arguments are the named arguments with assigned values being passed in the function call statement.

For example:-

def interest ( prin , time , rate ) :

       return prin * time * rate

      

print (interest ( prin = 2000 , time = 2 , rate 0.10 ))

 

print (interest ( time = 4 , prin = 2600 , rate = 0.09 ))

 

print (interest ( time = 2  , rate = 0.12  , prin = 2000 ))

 

• All the above functions call are valid now, even if the order of arguments does not match.

 

 

 

Using multiple argument type together:-

 

Python allows you to combine multiple argument types in a function call.

 

Rules for combining all three types of arguments:-

 

• And argument list must first contain positional (required) arguments followed by any keyword argument.

• Keyword arguments should be taken from the required arguments preferably.

• You cannot specify a value for an argument more than once.

For example:-

def interest ( prin , cc , time = 2 , rate = 0.09 ):

      return prin * time * rate

 

 


 


 



 

Thankyou !!!!!

 

For Sumita Arora Type C solution ( Programing Question ) Visit our YouTube Channel Portal Express

 

For Solution of Sumita Arora visit on Path Wala



31 Comments

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  1. how can i get the solution of unsolved questions??

    ReplyDelete
  2. Hi,Sir you have not provided the link below to download the notes, Please provide it.
    Thank you.

    ReplyDelete
  3. will this be enough for a small test? Has this note covered most of the patt?

    ReplyDelete
  4. Where is the topic scope of variables

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  5. This comment has been removed by the author.

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  6. new notes with new pattern please sirrrrrr

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  7. sir hello i want important mcq question of all the chapters because this year the exam is going to be mcq type sir plz help me .

    ReplyDelete
  8. PLEASE ADD CHAPTERWISE PDF OF THIS BOOK PLEASE.

    ReplyDelete
  9. Sir how to download the PDF of these notes . Plzzz tell me sir as soon as possible

    ReplyDelete
    Replies
    1. Take screen shot of these notes and make pdf and then note is ready for use

      Delete
  10. thanksπŸ‘πŸ‘πŸ‘

    ReplyDelete
  11. Notes after the topic "RETURNING VALUES FROM FUNCTION" are missing... Why are these topics left and not present there??? Please help me and reply....πŸ™πŸ»πŸ₯²

    ReplyDelete
  12. Open a youtube channel

    ReplyDelete
  13. Do you have youtube channnel

    ReplyDelete
    Replies
    1. I have channel it's name is Portal Express.

      Delete
  14. chalo chale ham exam dene abhi

    ReplyDelete

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