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Function in Python
This document discusses Python functions. It defines a function as a reusable block of code that performs a specific task. Functions help break programs into smaller, modular chunks. The key components of a function definition are the def keyword, the function name, parameters in parentheses, and a colon. Functions can take different types of arguments, including positional, default, keyword, and variable length arguments. Objects like lists, dictionaries, and sets are mutable and can change, while numbers, strings, tuples are immutable and cannot change. The document provides examples of passing list, tuples, and dictionaries to functions using techniques like tuples, asterisk operators, and double asterisk operators.
Function in Python
- 1. PYTHON FUNCTIONS BY: YASHDEV HADA PGTC.S. KV SECL DHANPURI
- 2. TOPIC COVERED 1. FUNCTION 2.CONCEPT 3. PARAMETER PASSING 4. TYPES OF FUNCTION 5. PROPERTIES OF FUNCTION 6. TYPES OF PARAMETERS 7. PASSING LIST TUPLES, DICTIONERIES 8. INBUILT FUNCTIONS
- 3. FUNCTION ISA GROUP OF RELATED STATEMENTS THAT PERFORM A SPECIFIC TASK. A FUNCTION CAN BE DEFINED AS THE ORGANIZED BLOCK OF REUSABLE CODE WHICH CAN BE CALLED WHENEVER REQUIRED FUNCTIONS HELP BREAK OUR PROGRAM INTO SMALLER AND MODULAR CHUCKS FUNCTION
- 4. DEFINING FUNCTION def marksthe start of function function name to uniquely identifya function. def function_name (parameter) : Argument to pass avalue in function colon(:) to mark end of function header
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- 6. A FUNCTION DEFINITIONCONSISTS OF FOLLOWING COMPONENTS
- 7. BRIEF COMPONENTS REQUIRED A FUNCTION IS DEFINED WITH KEYWORD ‘DEF’ WHICH IS FOLLWED BY NAME(UNIQUE) OF FUNCTION, THEN PARENTHESIS AND AFTER THAT ‘:’ EX. DEF SAMPLE() : A FUNCTION IS CALLED/INVOKED BY WRITING NAME OF FUNCTION EXAMPLE SAMPLE() A FUNCTION CAN BE CALLED NUMBER OF TIMES. THE ORDER IN WHICH FUNCTION IS CALLED AND THE ORDER IN WHICH FUNCTION IS DEFINED NEED NOT NECESSARILY BE SAME.
- 8. BRIEF COMPONENTS REQUIRED WHEN A FUNCTION IS CALLED THE CONTROL IS TRANSFERRED TO THE PLACE WHERE FUNCTION IS DEFINED AND WHEN EXECUTION/CALCULATIONC IS OVER THEN CONTROL IS RETURN BACK TO MAIN. A FUNCTION IS CALLED IN ANY OTHER FUNCTION BUT A FUNCTION CAN NOT BE DEFIND IN ANY OTHER FUNCTION. AN OPTIONAL RETURN STATEMENT TO RETURN A VALUE FROM THE FUNCTION.
- 9. TYPES OF FUNCTION (PASSING& RETURNING) BASICALLY THERE ARE 4 TYPES OF FUNCTION IN USE ON THE BASIS OF PASSING ARGUMENTS AND ACCEPTING IN PARAMETER :- NOT PASSING AND NOT RETURNING PASSING AND NOT RETURNING PASSING AND RETURNING NOT PASSING AND RETURNING *
- 10. PARAMETER & ARGUMENT PARAMENTERS ARE THE VALUE(S) PROVIDED IN THE PARENTHESIS WHEN WE WRITE FUNCTION HEADER. THESE ARE THE VALUES REQUIRED BY FUNCTION TO WORK. FOR EXAMPLE :--- def simp_int(p, r, t): ARGUMENTS ARE THE VALUE THAT IS PASSED TO THE FUNCTION WHEN IT IS CALLED. FOR EXAMPLE :--- simp_int(4000,5,10) PARAMENTERS ARGUMENTS
- 11. NOT PASSING ANDNOT RETURNING
- 12. PASSING AND NOTRETURNING
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- 14. NOT PASSING ANDRETURNING
- 15. TYPES OF ARGUMENTS 1. POSITIONAL ARGUMENTS 2. DEFAULT ARGUMENTS 3. KEYWORD ARGUMENTS 4. VARIABLE LENGTH ARGUMENTS
- 16. POSITIONAL ARGUMENTSARE THE ARGUMENTS PASSED TO A FUNCTION IN CORRECT POSITIONAL ORDER. IF WE CHANGE THE ORDER THEN THE RESULT IS CHANGED. POSITIONAL ARGUMENTS
- 17. Default valueto function argument is passed using assignment operator ‘ = ‘. Example: def sample(name, msg = "Good morning!"): print("Hello, " name + ', ' + msg) Non-default argument cannot follow default argument Example: def greet(msg = "Good morning!", name): SyntaxError: non-defaultargument followsdefaultargument DEFAULT ARGUMETNS
- 18. IF THEREIS A FUNCTION WITH MANY PARAMETER AND WE WANT TO SPECIFY ONLY SOME OF THEM IN FUNCTION CALL, THEN VALUE FOR SUCH PARAMETERS CAN BE PROVIDED BY THEIR NAME INSTEAD OF THE POSITION. SO IN KEYWORD ARGUMENTS WE CAN PASS ARGUMENTS VALUES BY KEYWORD I.E BY PARAMETER NAME KEYWORD ARGUMENTS
- 19. greet(name ="Bruce",msg = "How do you do?") 2 keyword arguments greet(msg = "How do you do?",name = "Bruce") 2 keyword arguments (out of order) greet("Bruce",msg = "How do you do?") 1 positional, 1 keyword argument greet(name="Bruce","How doyou do?") SyntaxError: non-keyword arg after keyword arg EXAMPLE OF KEYWORD ARGUMENTS
- 20. WHEN WEWRITE FUNCTION SUM TO ADD TWO NUMBER AND RETURN ADDITIION BACK THEN IT ADDS ALWAYS TWO VALUES. NOW IMAGINE WE WANT TO CREATE A SUM FUNCTION THAT CAN TAKE ANY NUMBER OF ARGUMENTS (LIKE 2,3,4,5…….) SO IN THIS SITUATION THE ABOVE SUM FUNCTION WE CAN PASS TWO ARGUMENTS. PYTHON ALLOWS US TO CREATE FUNCTION THAT CAN TAKE MULTIPLE ARGUMENTS. SUCH TYPE OF ARGUMENTS ARE CALLED VARIABLE LENGTH ARGUMENTS/PARAMETERS. VARIABLE LENGTH ARGUMENTS ARE DECLARED WITH * SYMBOL IN PYTHON VARIABLE LENGTH ARGUMENTS
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- 22. MUTABLE/IMMUTABLE PROPERTIES OFDATA OBJECTS A MUTABLE OBJECTS CAN CHANGE ITS STATE OR CONTENTS AND IMMUATABLE OBJECTS CANNOT. MUTABLE OBJECTS ARE : LIST,DICT,SET, BYTE ARRAY IMMUATABLE OBJECTS ARE: INT,FLOAT,COMPLEX,STRING,TUPLE,BYTES THE EXAMPLE SHOWING CONCEPT IS :-
- 23. MUTABLE/IMMUTABLE PROPERTIES OFDATA OBJECTS THE OBJECT IN WHICH X WAS TAGGED IS CHANGED. OBJECT 10 WAS NEVER MODIFIED. IMMUTABLE OBJECTS DOESN’T ALLOW MODIFICATION AFTER CREATING
- 24. MUTABLE/IMMUTABLE PROPERTIES OFDATA OBJECTS SO IT MEANS FROM ABOVE EXAMPLES: • PYTHON HANDLES MUTABLE AND IMMUATABLE OBJECTS DIFFERENTLY. • IMMUTABLE ARE QUICKER TO ACCESS THAN MUTABLE OBJECTS. • MUTABLE OBJECTS ARE GREAT TO USE WHEN YOU NEED TO CHANGE THE SIZE OF THE OBJECT, EXAMPLE LIST, DICT ETC. IMMUATABLE ARE USED WHEN YOU NEED TO ENSURE THAT EH OBJECT YOU MADE WILL STAY THE SAME. • IMMUTABLE OBJECTS ARE FUNDAMENTALLY EXPENSIVE TO “CHANGE” , BECAUSE DOING SO INVOLVES CREATING A COPY. CHANGING MUTABLES OBJECTS IS CHEAP.
- 25. A LISTCAN BE PASSED AS ARGUMENTS TO A FUNCTION SIMILAR TO PASSING NORMAL VARIABLE AS ARGUMENTS TO A FUNCTION: Method #1 : Using tuple() This task can be performed using the tuple(). In this, we convert the pair list to tuple and by this way we separate individual elements as variables, ready to be sent to function. PASSING ARRAYS/LISTS TO FUNCTION
- 26. Method #2: Using * operator Using * operator is the most recommended method to perform this task. The * operator unpacks the dual list into args and hence solving our problem.
- 28. The tuple()function is a built-in function in Python that can be used to create a tuple. A tuple is an immutable sequence type. PASSING TUPLES TO FUNCTION
- 29. Unpack elementsin dictionary to function arguments using ** Python provides an another symbol ** . On prefixing it with a dictionary, all the key value pairs in dictionary will be unpacked to function arguments. Let’s understand this by an example, . PASSING DICTIONERIS TO FUNCTION
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