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![list
Sequence of items separated by commas and the items enclosed in
square brackets[]
Ex:
>>>list1=[10,3.5,”new delhi”,’welcome’,50]
>>>print(list1)](https://image.slidesharecdn.com/2-250407050951-608d855d/85/2-Getting-Started-with-Python-second-lesson-pptx-22-320.jpg)
![INPUT, OUTPUT
• It accepts all user input as string
• Input([prompt])
• Input function terminated by pressing enter key](https://image.slidesharecdn.com/2-250407050951-608d855d/85/2-Getting-Started-with-Python-second-lesson-pptx-33-320.jpg)
![list
Sequence of items separated by commas and the items enclosed in
square brackets[]
Ex:
>>>list1=[10,3.5,”new delhi”,’welcome’,50]
>>>print(list1)](https://image.slidesharecdn.com/2-250407050951-608d855d/75/2-Getting-Started-with-Python-second-lesson-pptx-22-2048.jpg)
![INPUT, OUTPUT
• It accepts all user input as string
• Input([prompt])
• Input function terminated by pressing enter key](https://image.slidesharecdn.com/2-250407050951-608d855d/75/2-Getting-Started-with-Python-second-lesson-pptx-33-2048.jpg)
2. Getting Started with Python second lesson .pptx
- 1. Introduction of Python Whatis Python? Python is general Purpose High Level Programing Language It can be used For 1. Desktop Application 2. Web Application 3. Mobile Application
- 2. Popular apps developedin Python
- 3. About Python • Ithas very simple and straight forward Syntax. • Python is case sensitive Language. • It is an Object Oriented Programing Language. • Dynamically Typed . • Executed by interpreter • Can run in various operating systems. Indentation is used in place of Curly Braces. • Use variable without declaration. • It is an Interpreted Language.
- 4. Features • Emphasis onCode readability. • Automatic Memory Management. • Dynamically Typed • Large Library • Platform Independent
- 5. Features • Easy touse – Due to simple syntax rule • Interpreted language – Code execution & interpretation line by line • Cross-platform language – It can run on windows, Linux, Macintosh etc. equally • Expressive language – Less code to be written as it itself express the purpose of the code. • Completeness – Support wide rage of library • Free & Open Source – Can be downloaded freely and source code can be modify for improvement
- 6. Working with python •To run a python pgm, install a python interpreter at first • Interpreter is also called as python shell • >>>shows python prompt is ready to take instructions • We can type in this prompt to execute them using python interpreter
- 7. Two ways ofpython interpreter • Interactive mode • Script mode
- 8. Interactive mode • Simplytype in >>> prompt. • Immediately executed of individual statement • Convini ent for testing single line code for instant execution • We cannot save the statements for future use • Retype and run again • Eg: • 1+2 • Answer we get immediately
- 9. Script mode • Ina file, we type, save then execute it • Extension is .py • Tell the students to write a program to show print statements in script mode
- 10. Python keywords • Reservedwords • Each word has a specific meaning • we use keyword only for the purpose for which it has been defined • Python is Case sensitive , so exactly we have to write
- 11. • We cannotuse a keyword as a variable name, function name or any other identifier. They are used to define the syntax and structure of the Python language. • In Python, keywords are case sensitive. • There are 33 keywords in Python 3.7. This number can vary slightly over the course of time. • All the keywords except True, False and None are in lowercase and they must be written as they are..
- 12. List of keywords
- 13. identifiers • Used toidentify a variable, function or entity in program • Identifiers can be a combination of letters in lowercase (a to z) or uppercase (A to Z) or digits (0 to 9) or an underscore _ . ... • An identifier cannot start with a digit. ... • Keywords cannot be used as identifiers. ... • We cannot use special symbols like !, @, #, $, % etc. ... • An identifier can be of any length. • Ex: marks 1, mark2, avg like that words used to identify by us for write a program • Area=length*breadth
- 14. variables •A variable isa label that you can assign a value to it. The value of a variable can change throughout the program. •A=‘m’ •Message=“keep smiling” •Price=587.6
- 15. comments • Remark ornote in the source code • Easier for other persons also to understand • #sign starts till end of # considered as comment • Simply ignores while executing the statement
- 16. Data types Variables canstore data of different types, and different types can do different things. Python has the following data types built-in by default, in these categories:
- 18. Numbers or numeric Typedescription example Int integer numbers -12,-3,0,125 Float real or floating numbers -2.04, 4.0, 14.23 Complex complex numbers 3+4i, 2-2i
- 19. Boolean (bool) • Itis a subtype of integer • It is a unique data type • Consists of two constants (True and False) • Boolean True value is non-zero, non null, non empty • Boolean False is value zero
- 20. sequence Ordered collection ofitems • String • List • tuple
- 21. string •– group ofcharacters •->>>str1=‘hello’ •->>>str2=“452” •We cannot perform numerical operations on strings, even when the string contains a value as in str2
- 22. list Sequence of itemsseparated by commas and the items enclosed in square brackets[] Ex: >>>list1=[10,3.5,”new delhi”,’welcome’,50] >>>print(list1)
- 23. tuple • Sequence ofitems separated by commas and the items enclosed in parenthesis() • Ex • Tuple1=(10,20,”apple”,3.4,’a’) • Print(tuple1)
- 24. SET • Unordered collectionof items • {} • No duplicate entries • Ex • Set1={10,20,10,’apple’} • Print(type(set1)) • <class’set’> • Print(set1) • Output{10,20,’apple’}
- 25. NONE • Special datatype with a single value • Used to signify the absence of value in a situation • None supports no special operations, and it is neither false nor zero
- 26. mapping • Unordered datatype •One standard mapping datatype is called dictionary • Holds data items in key value pairs • {} • Dictionaries permit faster access to data • Every key is separated from its value using a colon: sign • >>>dict1={‘fruit’:’apple’,’climate’:’cold’} • Print(dict1)
- 27. Mutable and immutabledata types • List and dictionary are mutable datatypes • Refer page no 98 in NCERT BOOK • MEMORY ALLOCATION OF num1, num2, num1=num1+100
- 28. Deciding usage ofpython data types • For storing names of students, easy to update when new admission join • Tuples use when no change ex- names of months in a year • When need uniqueness , avoid duplicacy, we use sets • When we need logical association between the key:value pair, advising to use dictionaries • Ex: mobile phone book is a good application of dictionary
- 29. operators • To performmathematical or logical operation on values • Values that the operators work on are called operands • Ex: 10+num, • Value is 10 • Variable num operands and the + sign is an operator
- 30. Arithmetic operators RELATIONAL OPERATORS assignmentoperators logical operators identity operators membership operator •Pg no 100 to 104 in NCERT BOOK to be work out in lab
- 31. expression • Combination ofconstants, variables and operators • Always evaluates a value • A value or variable is also considered as an expression but a standalone operator is not an expression • Precedence Of expression refer pg 105 in NCERT
- 32. STATEMENT • IN PYTHON,A STATEMENT IS A UNIT OF CODE THAT THE PYTHON INTERPRETER CAN EXECUTE PG NO 106 IN NCERT BOOK
- 33. INPUT, OUTPUT • Itaccepts all user input as string • Input([prompt]) • Input function terminated by pressing enter key
- 34. Type conversion • Pgno 108,109 in NCERT BOOK • IMPLICIT , EXPLICIT CONVERSION
- 35. DEBUGGING • SYNTAX ERRORS •LOGICAL ERRORS • RUNTIME ERRORS
- 36.