PYTHON FUNDAMENTAL (CLASS - XI) PART -2

PYTHON FUNDAMENTAL

CHAPTER -IV (PART - 2)

CLASS – XI

Operators

Operators can be defined as symbols that are used to perform operations on operands. In other word, operators are tokens that trigger some computation when applied to variables and other objects in an expression. Variables and objects to which the computation is applied, are called operands.

Types of Operators

1. Arithmetic Operators

2. Relational Operators

3. Assignment Operators

4. Bitwise Operators

5. Logical Operators

6. Membership Operators

7. Identity Operators

1. Arithmetic Operators: It is used to perfor arithmetic operations like addition, subtraction, multiplication, division etc

Operators	Description	Example
+	Perform addition of two number	x+y
-	Perform subtraction of two number	x-y
/	Perform division of two number	x/y
*	Perform multiplication of two number	x*y
%	Modules = return remainder	x%y
//	Floor Division = remove digits after the decimal point	x//y
**	Exponent = perform raise to power	x**y

2. Relational Operators: Relational operators are used to compare the values.

Operators	Description	Example
==	Equal to, return true if x equal to y	x == y
!=	Not equal, return true if x is not equals to y	x ! = y
>	Greater than, return true if x is greater than y	x > y
>=	Greater than or equal to, return true if x is greater than y or x is equals to y	x >= y
<	Less than, return true if x is less than y	x < y
<=	Less than or equal to, return true if x is less than y or x is equals to y	x <= y

3. Assignment Operators: Used to assign values to the variables.

Operators	Description	Example
=	Assigns calues from right side operands to left side operand	x=y
+=	Add 2 numbers and assigns the result to left operand.	x+=y
/=	Divide 2 numbers and assigns the result to left operand.	x/=y
*=	Multiply 2 numbers and assigns the result to left operand.	x*=y
-=	Subscrats 2 numbers and assigns the result to left operand.	x-=y
%=	Modules 2 numbers and assigns the result to left operand.	x%=y
//=	Perform floor division on two numbers and assigns the result to left operand.	x//=y
**=	Calculate power on operators and assigns the result to left operand.	x**=y

4. Logical Operators: It is performed logical operations on the given two variables or values.

Operators	Description	Example
and	Return true if both conditions are true	x and y
or	Return true if either or both conditions are true	x or y
not	Reverse the condition	Not(x>y)

Example:

x = 5

y = 10

if(x==5 and y==10):

print(“Hello Python”)

Output

Hello Python

5. Membership Operators: The membership operators in Python are used to validate whether a value is found within a sequence such as strings, lists, or tuples.

Operators	Description	Example
in	Return true if value exists in sequence, else false.	a in list
not in	Return true if value does not exists in sequence, else false.	a not in list

Example:

a = 10

list = [10, 20, 30, 40, 50]

y = a in list

z = a not in list

print(y)

print(z)

Output:

True

False

6. Identity Operators: Identity operators in Python compare the memory of two objects.

Operators	Description	Example
is	Return true if variables point the same object, else false.	a is b
is not	Returns true if two variables point the different object, else false.	a is not b

Example:

a = 15

b = 14

if(a is b):

print(“Both a and b has same identity”)

else:

print(“a and b has different identity”)

b = 75

if (a is b):

print(“Both a and b has same identity”)

else:

print(“a and b has different identity”)

Output:

Both a and b has same identity

a and b has different identity

7. Bitwise Operators:

Operators	Description	Example
&	Bitwise AND	a & b
^	Bitwise exclusive OR (XOR)	a ^ b
|	Bitwise OR	a | b

Punctuators: Punctuators are symbols that are used in programming languages to organize sentence structures, and indicate the rhythm and emphasis of expressions, statements, and program structure.

Most common punctuators are:

Barebones of a Python Program: Now we are going to talk about the basic structure of a Python program – what all it can contain. Before we proceed, have a look at following sample code.

A Python program contain the following components

a. Expression

b. Statement

c. Comments

d. Function

e. Block & Indentation

a. Expression: Which is evaluated and produce result. E.g. (20+5)/5

b. Statement: Instruction that does something. E.g.

                                             a = 25

                                             print (“Calling in proper sequence”)

c. Comments: Which is readable for programmer but ignored by python interpreter.

               1. Single line comment: Which begins with # sign.

               2. Multi line comment (docstring): either write multiple line beginning with # sign or use

      triple quoted multiple line. E.g.

               ‘’’this is my

                     First python

                    Multi line comment

               ‘’’

d. Function: A code that has some name and it can reused. E.g. keyArgFunc in above program

e. Block & indentation: Group of statements is block. Indentation at same level create a block. E.g.  all 3 statement of keyArgFunc function

VARIABLES: amed labels, whose values can be used and processed during program run, are called Variables.

Assigning Values To Variable

name = ‘Python’               # String Data Type

sum = None                       # variable without value

a = 35                                  # Integer

b = 5.5                                 # Float

sum = a + b

print(sum)

Multiple Assignment: Assign a single value to many variables like

a = b = c = 1        # single value to multiple variable

a, b = 5, 6            # multiple value to multiple variables

a, b = b, a                           =# value of a and b is swaped

Variable Scope And Lifetime in Python Program

1. Local Variable

               def fun():

                              x = 10

                              print (x)

               fun()

               print(x) #error will be shown

2. Global Variable

               x = 15   

               def fun():

                              print(x)  # Calling variable ‘x’ inside fun()

               fun()

               print(x)  # Calling variable ‘x’ outside fun()

Dynamic Typing

Data type of a variable depend/change upon the value assigned to a variable on each next statement.

X = 40                   # integer type

X = ‘Hello’           # X variable data type change to string on just next line

Now programmer should be aware that not to write like this:

Y = X/5 # error because String cannot be devided.

Input and Output

print() Function in Python is used to print output on the screen.

Syntax of Print

               print(expression/variable)

e.g. print(95)

Output: 95

 

print(‘Hello Python!’)

Output: Hello Python!

print(‘Informatics’, ‘Practices’)

print(‘Informatics’ ‘Practices’, sep = ‘&’)

print(‘Informatics’ ‘Practices’, sep = ‘&’, end=’.’)

Output:

Informatics Practices

Informatics & Practices

Informatics & Practices.

Note: This is the notes of Chapter -4 PYTHON FUNDAMENTAL (SECOND PART). It is important for every students. By the help of these notes students can prepare for their Exam.

!!! THANK YOU !!!

PYTHON FUNDAMENTAL (CLASS - XI) PART - 1

PYTHON FUNDAMENTAL

CHAPTER -IV (PART - 1)

CLASS – XI

INTRODUCTION

In this chapter, we will learn about all basic elements that a python program can contain. You’ll be learning about Python’s basics like Character set, tokens, expressions, statements, simple input and output etc.

Python Character Set: A set of valid characters recognized by python. Python uses the traditional ASCII character set. The latest version recognizes the Unicode character set. The ASCII character set is a subset of the Unicode character set.

Letters: A-Z, a-z

Digits: 0 to 9

Special Symbols: Special symbol available over keyboard like +, -, ( ), *, & ^ %, !, @, # , etc.

White Space: Blank space, tab, carriage return, new line, form feed.

Other Characters: Python can process all ASCII and Unicode characters as part of data or literals.

Example:

a1 = ‘Informatics Practices’

b1 = ‘Computer Science

print (‘a1’, and, ‘b1’)

The output will be

Informatics Practices and Computer Science

raw_input(): Function in Python allow a user to give input to a program from a keyboard but in the form of string

Exampe:

name =int(input(“Enter your Name”))

age = int(input(“Enter your Age”))

per = float(input(“Enter your Percentage”))

Token

The smallest individual unit in a program is known as a Token or a lexical unit.

1. Keywords

2. Identifiers

3. Literals

4. Operators

5. Punctuators

Keywords: Reverse words of the compiler/interpreter which can’t be used as identifier.

and	Del	is	yield	not
as	For	pass	expect	try
assert	In	with	if	False
break	Or	else	nonlocal	True
class	While	global	return	None
continue	Elif	lambda	finally
def	From	raise	import

Identifiers: A Python identifier is a name used to identify a variable, function, class module, list, dictionaries or other objects.

Some important points for identifier:

An identifier starts with a letter A to Z or a to z or and underscore(_) followed by zero or more letters, underscore and digits (0 to 9).

Python does not allow special characters.

Identifier must not be a keywords of Python.

Python is a case sensitive programming language. Thus, Rollno and rollno are two different identifiers in Python.

Example of valid and invalid identifiers

Valid: Myname, file123, Y2ad, date_2, _no

Invalid: 2rno, break, my.name, data-cs

Literals: Literals in Python can be defined as number, text, or other data that represent values to be stored in variables. Python allows several kinds of literals: (i) String (ii) Numeric (iii) Boolean (iv) Special literal (v) Literal collections

Example of String Literals

name = ‘Shekhar’             ,              fname = “shekhar”

Example of Integer Literal (Numeric Literal)

age = 15

Example of Special Literals

name = None

Escape Sequence in Python

Escape Sequence	Description
\\	Backslash (\)
\’	Single quote (‘)
\”	Double quote(“)
\a	ASCII Bell (BEL)
\b	ASCII Backspace (BS)
\f	ASCII Formeed (FF)
\n	ASCII Linefeed (LF)
\r	ASCII Carriage Return (CR)
\t	ASCII Horizontal Tab (TAB)
\v	ASCII Vertical Tab (VT)
\ooo	Character with octal value
\xhh	Character with hex value hh

Note: This is the notes of Chapter -4 PYTHON FUNDAMENTAL (FIRST PART). It is important for every students. By the help of these notes students can prepare for their Exam.

!!! THANK YOU !!!