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New, syllabus, 2020-21, Chapter 1, Revision of the, Basics of Python, , Computer Science, Class XII ( As per CBSE Board), Visit : python.mykvs.in for regular updates
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Introduction, It is widely used general purpose,high level programming, language.Developed by Guido van Rossum in 1991., , It is used for:, software development,, web development (server-side),, system scripting,, Mathematics., , Visit : python.mykvs.in for regular updates
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Features of Python, 1. Easy to use – Due to simple syntax rule, 2. Interpreted language – Code execution &, interpretation line by line, 3. Cross-platform language – It can run on, windows,linux,macinetosh etc. equally, 4. Expressive language – Less code to be written as it, itself express the purpose of the code., 5. Completeness – Support wide rage of library, 6. Free & Open Source – Can be downloaded freely, and source code can be modify for improvement, Visit : python.mykvs.in for regular updates
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Shortcomings of Python, 1. Lesser libraries – as compared to other, programming languages like c++,java,.net, 2. Slow language – as it is interpreted languages,it, executes the program slowly., 3. Weak on Type-binding – It not pin point on use of a, single variable for different data type., , Visit : python.mykvs.in for regular updates
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How to work in Python, (i) in Interactive mode, * Search the python.exe file in the drive in which it is, installed., If found double click it to start python in interactive, mode, , Visit : python.mykvs.in for regular updates
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How to work in Python, * Click start button -> All programs, , ->, , python<version>->IDLE(Python GUI), , Visit : python.mykvs.in for regular updates
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How to work in Python, Python command, prompt >>>, , Type the following at prompt, print “hello”, print 8*3, print 3**3, k=3+4*3, print k, , Visit : python.mykvs.in for regular updates
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How to work in Python, (ii) in Script mode, Step 1 (Create program file), Below steps are for simple hello world program, , a. Click Start button->All Programs, , ->, , Python<version>->IDLE, b. Now click File->New in IDLE Python Shell, Now type, print “hello”, print “world”, print “python is”,”object oriented programming lang.”, , c. Click File->Save and then save the file with filename, and .py extension, Visit : python.mykvs.in for regular updates
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How to work in Python, , (ii) in Script mode, Step 2 (Run program file), a., b., c., , Click Open command from IDLE’s File menu and select, the file you have already saved, Click Run-> Run Module, It will execute all the commands of program file and, display output in separate python shell window, , Note :- Python comes in 2 flavours – python 2.x and python 3.x . Later one is, Backward incompatible language as decide by Python Software foundation(PSF)., Mean code written in 2.x will not execute on 3.x . Visit the below link for difference, between 2.x & 3.x, https://www.geeksforgeeks.org/important-differences-between-python-2-x-andpython-3-x-with-examples/, Visit : python.mykvs.in for regular updates
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Data Handling, Most of the computer programming language, support data type, variables,operator and expression like, fundamentals.Python also support these., Data Types, Data Type specifies which type of value a variable can store., type() function is used to determine a variable's type in, Python., , Visit : python.mykvs.in for regular updates
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Data type continue, Data Types In Python, 1. Number, 2. String, 3. Boolean, 4. List, 5. Tuple, 6. Set, 7. Dictionary, , Visit : python.mykvs.in for regular updates
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Data type continue, 1. Number In Python, It is used to store numeric values, Python has three numeric types:, 1. Integers, 2. Floating point numbers, 3. Complex numbers., , Visit : python.mykvs.in for regular updates
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Data type continue, 1. Integers, Integers or int are positive or negative, numbers with no decimal point. Integers in Python, 3 are of unlimited size., e.g., a= 100, b= -100, c= 1*20, print(a), print(b), print(c), Output :100, -100, 200, Visit : python.mykvs.in for regular updates
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Data type continue, Type Conversion of Integer, int() function converts any data type to integer., e.g., a = "101" # string, b=int(a) # converts string data type to integer., c=int(122.4) # converts float data type to integer., print(b), print(c)Run Code, Output :101, 122, Visit : python.mykvs.in for regular updates
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Data type continue, 2. Floating point numbers, It is a positive or negative real numbers with, a decimal point., e.g., a = 101.2, b = -101.4, c = 111.23, d = 2.3*3, print(a), print(b), print(c), print(d)Run Code, Output :101.2, -101.4, 111.23, 6.8999999999999995, , Visit : python.mykvs.in for regular updates
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Data type continue, Type Conversion of Floating point numbers, float() function converts any data type to floating point, number., , e.g., a='301.4' #string, b=float(a) #converts string data type to floating point number., c=float(121) #converts integer data type to floating point number., print(b), print(c)Run Code, Output :301.4, 121.0, , Visit : python.mykvs.in for regular updates
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Data type continue, 3. Complex numbers, Complex numbers are combination of a real, and imaginary part.Complex numbers are in the form, of X+Yj, where X is a real part and Y is imaginary part., e.g., a = complex(5) # convert 5 to a real part val and zero imaginary part, print(a), b=complex(101,23) #convert 101 with real part and 23 as imaginary part, print(b)Run Code, Output :(5+0j), (101+23j), Visit : python.mykvs.in for regular updates
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Data type continue, Iterating through string, e.g., str='comp sc', for i in str:, print(i), Output, c, o, m, p, s, c, Visit : python.mykvs.in for regular updates
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Data type continue, 3. Boolean In Python, It is used to store two possible values either true or, false, e.g., str="comp sc", boo=str.isupper() # test if string contains upper case, print(boo), Output, False, Visit : python.mykvs.in for regular updates
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Data type continue, 4.List In Python, List are collections of items and each item has its own index value., , 5. Tuple In Python, List and tuple, both are same except ,a list is mutable python objects and tuple is, immutable Python objects. Immutable Python objects mean you cannot modify the, contents of a tuple once it is assigned., , e.g. of list, list =[6,9], list[0]=55, print(list[0]), print(list[1]), , e.g. of tuple, tup=(66,99), Tup[0]=3 # error message will be displayed, print(tup[0]), print(tup[1]), , OUTPUT, 55, 9, Visit : python.mykvs.in for regular updates
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Data type continue, 6. Set In Python, It is an unordered collection of unique and, immutable (which cannot be modified)items., e.g., set1={11,22,33,22}, print(set1), , Output, {33, 11, 22}, Visit : python.mykvs.in for regular updates
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Data type continue, 7. Dictionary In Python, It is an unordered collection of items and each item, consist of a key and a value., e.g., dict = {'Subject': 'comp sc', 'class': '11'}, print(dict), print ("Subject : ", dict['Subject']), print ("class : ", dict.get('class')), , Output, {'Subject': 'comp sc', 'class': '11'}, Subject : comp sc, class : 11, Visit : python.mykvs.in for regular updates
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Operator, Operators are special symbols in Python that carry out arithmetic or logical, computation. The value that the operator operates on is called the operand., , Arithmetic operators, Used for mathematical operation, Operator Meaning, , Example, , +, , Add two operands or unary plus, , x+y, +2, , -, , Subtract right operand from the left or unary minus, , x-y, -2, , *, , Multiply two operands, , x*y, , /, , Divide left operand by the right one (always results into float), , x/y, , %, , Modulus - remainder of the division of left operand by the right x % y (remainder of x/y), , //, , Floor division - division that results into whole number, adjusted to the left in the number line, , x // y, , **, , Exponent - left operand raised to the power of right, , x**y (x to the power y), , Visit : python.mykvs.in for regular updates
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Operator continue, Arithmatic operator continue, e.g., x=5, y=4, print('x + y =',x+y), print('x - y =',x-y), print('x * y =',x*y), print('x / y =',x/y), print('x // y =',x//y), print('x ** y =',x**y), OUTPUT, ('x + y =', 9), ('x - y =', 1), ('x * y =', 20), • Write a program in python to calculate the simple, ('x / y =', 1), interest based on entered amount ,rate and time, ('x // y =', 1), ('x ** y =', 625), Visit : python.mykvs.in for regular updates
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Operator continue, Arithmatic operator continue, # EMI Calculator program in Python, def emi_calculator(p, r, t):, r = r / (12 * 100) # one month interest, t = t * 12 # one month period, emi = (p * r * pow(1 + r, t)) / (pow(1 + r, t) - 1), return emi, # driver code, principal = 10000;, rate = 10;, time = 2;, emi = emi_calculator(principal, rate, time);, print("Monthly EMI is= ", emi), Visit : python.mykvs.in for regular updates
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Operator continue, Comparison operators -used to compare values, Operator, , Meaning, , Example, , >, , Greater that - True if left operand is greater than the right, , x>y, , <, , Less that - True if left operand is less than the right, , x<y, , ==, , Equal to - True if both operands are equal, , x == y, , !=, , Not equal to - True if operands are not equal, , x != y, , >=, , Greater than or equal to - True if left operand is greater than or equal to, the right, , x >= y, , <=, , Less than or equal to - True if left operand is less than or equal to the right, , x <= y, , Visit : python.mykvs.in for regular updates
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Operator continue, Comparison operators continue, e.g., x = 101, y = 121, print('x > y is',x>y), print('x < y is',x<y), print('x == y is',x==y), print('x != y is',x!=y), print('x >= y is',x>=y), print('x <= y is',x<=y), Output, ('x > y is', False), ('x < y is', True), ('x == y is', False), ('x != y is', True), ('x >= y is', False), ('x <= y is', True), , Visit : python.mykvs.in for regular updates
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Operator continue, Logical operators, Operator, , Meaning, , Example, , and, , True if both the operands are true, , x and y, , or, , True if either of the operands is true, , x or y, , not, True if operand is false (complements the operand), e.g., x = True, y = False, print('x and y is',x and y), print('x or y is',x or y), print('not x is',not x), Outpur, ('x and y is', False), ('x or y is', True), ('not x is', False), , Visit : python.mykvs.in for regular updates, , not x
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Operator continue, Bitwise operators, Used to manipulate bit values., , Operator, , Meaning, , Example, , &, , Bitwise AND, , x& y, , |, , Bitwise OR, , x|y, , ~, , Bitwise NOT, , ~x, , ^, , Bitwise XOR, , x^y, , >>, , Bitwise right shift, , x>> 2, , <<, , Bitwise left shift, , x<< 2, , Visit : python.mykvs.in for regular updates
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Operator continue, Bitwise operators continue, a=6, b=3, print ('a=',a,':',bin(a),'b=',b,':',bin(b)), c=0, c = a & b;, print ("result of AND is ", c,':',bin(c)), c = a | b;, print ("result of OR is ", c,':',bin(c)), c = a ^ b;, print ("result of EXOR is ", c,':',bin(c)), c = ~a;, print ("result of COMPLEMENT is ", c,':',bin(c)), c = a << 2;, print ("result of LEFT SHIFT is ", c,':',bin(c)), c = a >> 2;, print ("result of RIGHT SHIFT is ", c,':',bin(c)), , Output, ('a=', 6, ':', '0b110', 'b=', 3, ':', '0b11'), ('result of AND is ', 2, ':', '0b10'), ('result of OR is ', 7, ':', '0b111'), ('result of EXOR is ', 5, ':', '0b101'), ('result of COMPLEMENT is ', -7, ':', '-0b111'), ('result of LEFT SHIFT is ', 24, ':', '0b11000'), ('result of RIGHT SHIFT is ', 1, ':', '0b1'), , Visit : python.mykvs.in for regular updates
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Operator continue, Python Membership Operators, Test for membership in a sequence, Operator, , Description, , in, , Evaluates to true if it finds a variable in the specified sequence and false otherwise., , not in, , Evaluates to true if it does not finds a variable in the specified sequence and false otherwise., , e.g., a=5, b = 10, list = [1, 2, 3, 4, 5, if ( a in list ):, print ("Line 1 - a, else:, print ("Line 1 - a, if ( b not in list ):, print ("Line 2 - b, else:, print ("Line 2 - b, , ], is available in the given list"), is not available in the given list"), is not available in the given list"), is available in the given list"), , Visit : python.mykvs.in for regular updates, , output, Line 1 - a is available in the given list, Line 2 - b is not available in the given, , list
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Operator continue, Python Identity Operators, Operat, or, , Description, , is, , Evaluates to true if the variables on either side of the operator point to the same, object and false otherwise., , is not, , Evaluates to false if the variables on either side of the operator point to the same, object and true otherwise., , e.g., a = 10, b = 10, print ('Line 1','a=',a,':',id(a), 'b=',b,':',id(b)), if ( a is b ):, print ("Line 2 - a and b have same identity"), else:, print ("Line 2 - a and b do not have same identity"), OUTPUT, ('Line 1', 'a=', 10, ':', 20839436, 'b=', 10, ':', 20839436), Line 2 - a and b have same identity, Visit : python.mykvs.in for regular updates
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Operator continue, Operators Precedence :highest precedence to lowest precedence table, Operator, , Description, , **, , Exponentiation (raise to the power), , ~+-, , Complement, unary plus and minus (method names for the last two are +@ and -@), , * / % //, , Multiply, divide, modulo and floor division, , +-, , Addition and subtraction, , >> <<, , Right and left bitwise shift, , &, , Bitwise 'AND'td>, , ^|, , Bitwise exclusive `OR' and regular `OR', , <= < > >=, , Comparison operators, , <> == !=, , Equality operators, , = %= /= //= -= += Assignment operators, *= **=, is is not, , Identity operators, , in not in, , Membership operators, , not or and, , Logical operators, , Visit : python.mykvs.in for regular updates
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Expression, It is a valid combination of operators,literals and, variable., 1. Arithmatic expression :- e.g. c=a+b, 2. Relational expression :- e.g. x>y, 3. Logical expression :- a or b, 4. String expression :- c=“comp”+”sc”, , Visit : python.mykvs.in for regular updates
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Type conversion, The process of converting the value of one data type (integer, string, float, etc.) to another, data type is called type conversion., Python has two types of type conversion., Implicit Type Conversion, Explicit Type Conversion, , Implicit Type Conversion:, In Implicit type conversion, Python automatically converts one data type to another data, type. This process doesn't need any user involvement., e.g., num_int = 12, num_flo = 10.23, num_new = num_int + num_flo, print("datatype of num_int:",type(num_int)), print("datatype of num_flo:",type(num_flo)), print("Value of num_new:",num_new), print("datatype of num_new:",type(num_new)), , OUTPUT, ('datatype of num_int:', <type 'int'>), ('datatype of num_flo:', <type 'float'>), ('Value of num_new:', 22.23), ('datatype of num_new:', <type 'float'>), , Visit : python.mykvs.in for regular updates
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Type conversion, Explicit Type Conversion:, In Explicit Type Conversion, users convert the data type of an object to required, data type. We use the predefined functions like int(),float(),str() etc., e.g., num_int = 12, num_str = "45", print("Data type of num_int:",type(num_int)), print("Data type of num_str before Type Casting:",type(num_str)), num_str = int(num_str), print("Data type of num_str after Type Casting:",type(num_str)), num_sum = num_int + num_str, print("Sum of num_int and num_str:",num_sum), print("Data type of the sum:",type(num_sum)), OUTPUT, ('Data type of num_int:', <type 'int'>), ('Data type of num_str before Type Casting:', <type 'str'>), ('Data type of num_str after Type Casting:', <type 'int'>), ('Sum of num_int and num_str:', 57), ('Data type of the sum:', <type 'int'>), , Visit : python.mykvs.in for regular updates
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math module, It is a standard module in Python. To use mathematical functions of this module,we, have to import the module using import math., Function, , Example, , Description, , ceil(n), , It returns the smallest integer greater than or equal to n., , math.ceil(4.2) returns 5, , factorial(n), , It returns the factorial of value n, , math.factorial(4) returns 24, , floor(n), , It returns the largest integer less than or equal to n, , math.floor(4.2) returns 4, , fmod(x, y), , It returns the remainder when n is divided by y, , math.fmod(10.5,2) returns 0.5, , exp(n), , It returns e**n, , math.exp(1) return 2.718281828459045, , log2(n), , It returns the base-2 logarithm of n, , math.log2(4) return 2.0, , log10(n), , It returns the base-10 logarithm of n, , math.log10(4) returns 0.6020599913279624, , pow(n, y), , It returns n raised to the power y, , math.pow(2,3) returns 8.0, , sqrt(n), , It returns the square root of n, , math.sqrt(100) returns 10.0, , cos(n), , It returns the cosine of n, , math.cos(100) returns 0.8623188722876839, , sin(n), , It returns the sine of n, , math.sin(100) returns -0.5063656411097588, , tan(n), , It returns the tangent of n, , math.tan(100) returns -0.5872139151569291, , pi, , It is pi value (3.14159...), , It is (3.14159...), , e, , It is mathematical constant e (2.71828...), , It is (2.71828...), , Visit : python.mykvs.in for regular updates
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Control Statements, Control statements are used to control the flow of, execution depending upon the specified condition/logic., There are three types of control statements., 1. Decision Making Statements, 2. Iteration Statements (Loops), 3. Jump Statements (break, continue, pass), , Visit : python.mykvs.in for regular updates
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Decision Making Statement, Decision making statement used to control the flow, of execution of program depending upon condition., , There are three types of decision making statement., 1. if statements, 2. if-else statements, 3. Nested if-else statement, , Visit : python.mykvs.in for regular updates
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Decision Making Statement, 1. if statements, An if statement is a programming conditional, statement that, if proved true, performs a function, or displays information., , Visit : python.mykvs.in for regular updates
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Decision Making Statement, 1. if statements, Syntax:, if(condition):, statement, [statements], e.g., noofbooks = 2, if (noofbooks == 2):, print('You have '), print(‘two books’), print(‘outside of if statement’), Output, You have two books, Note:To indicate a block of code in Python, you must indent each line of, the block by the same amount. In above e.g. both print statements are, part of if condition because of both are at same level indented but not, the third print statement., Visit : python.mykvs.in for regular updates
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Decision Making Statement, 1. if statements, Using logical operator in if statement, x=1, y=2, if(x==1 and y==2):, print(‘condition matcing the criteria'), Output :condition matcing the criteria, , ----------------------------------------------------------a=100, if not(a == 20):, print('a is not equal to 20'), Output :a is not equal to 20, Visit : python.mykvs.in for regular updates
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Decision Making Statement, 2. if-else Statements, If-else statement executes some code if the test expression is true, (nonzero) and some other code if the test expression is false., , Visit : python.mykvs.in for regular updates
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Decision Making Statement, 2. if-else Statements, Syntax:, , if(condition):, statements, else:, statements, e.g., a=10, if(a < 100):, print(‘less than 100'), else:, print(‘more than equal 100'), OUTPUT, less than 100, *Write a program in python to check that entered numer is even or odd, Visit : python.mykvs.in for regular updates
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Decision Making Statement, 3. Nested if-else statement, The nested if...else statement allows you to check for multiple test, expressions and execute different codes for more than two, conditions., , Visit : python.mykvs.in for regular updates
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Decision Making Statement, 3. Nested, , if-else statement, , Syntax, If (condition):, statements, elif (condition):, statements, else:, statements, E.G., num = float(input("Enter a number: ")), if num >= 0:, if num == 0:, print("Zero"), else:, print("Positive number"), else:, print("Negative number"), OUTPUT, Enter a number: 5, Positive number, * Write python program to find out largest of 3 numbers., , Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), Iteration statements(loop) are used to execute a block of, statements as long as the condition is true., Loops statements are used when we need to run same code, again and again., Python Iteration (Loops) statements are of three type :-, , 1. While Loop, 2. For Loop, , 3. Nested For Loops, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 1. While Loop, It is used to execute a block of statement as long as a given, condition is true. And when the condition become false, the, control will come out of the loop. The condition is checked every, time at the beginning of the loop., Syntax, while (condition):, statement, [statements], , e.g., x=1, while (x <= 4):, print(x), x=x+1, , Output, 1, 2, 3, 4, , Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), While Loop continue, While Loop With Else, e.g., x=1, while (x < 3):, print('inside while loop value of x is ',x), x=x+1, else:, print('inside else value of x is ', x), Output, inside while loop value of x is 1, inside while loop value of x is 2, inside else value of x is 5, *Write a program in python to find out the factorial of a given number, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), While Loop continue, Infinite While Loop, e.g., x=5, while (x == 5):, print(‘inside loop'), Output, Inside loop, Inside loop, …, …, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 2. For Loop, It is used to iterate over items of any sequence, such as a list, or a string., Syntax, for val in sequence:, statements, e.g., for i in range(3,5):, print(i), Output, 3, 4, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 2. For Loop continue, Example programs, for i in range(5,3,-1):, print(i), Output, 5, 4, range() Function Parameters, start: Starting number of the sequence., stop: Generate numbers up to, but not including this number., step(Optional): Determines the increment between each numbers in the, sequence., Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 2. For Loop continue, For Loop With Else, e.g., for i in range(1, 4):, print(i), else: # Executed because no break in for, print("No Break"), , Output, 1, 2, 3, 4, No Break, , Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 2. For Loop continue, Nested For Loop, e.g., for i in range(1,3):, for j in range(1,11):, k=i*j, print (k, end=' '), print(), , Output, 1 2 3 4 5 6 7 8 9 10, 2 4 6 8 10 12 14 16 18 20, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 3. Jump Statements, Jump, statements, are, used, to, transfer, the program's control from one location to another. Means, these are used to alter the flow of a loop like - to skip a part, of a loop or terminate a loop, , There are three types of jump statements used in python., 1.break, 2.continue, 3.pass, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 1.break, it is used to terminate the loop., e.g., for val in "string":, if val == "i":, break, print(val), print("The end"), , Output, s, t, r, The end, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 2.continue, It is used to skip all the remaining statements in the, loop and move controls back to the top of the loop., e.g., for val in "init":, if val == "i":, continue, print(val), print("The end"), Output, n, t, The end, , Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 3. pass Statement, This statement does nothing. It can be used when a statement is, required syntactically but the program requires no action., Use in loop, while True:, pass # Busy-wait for keyboard interrupt (Ctrl+C), , In function, It makes a controller to pass by without executing any code., e.g., def myfun():, pass #if we don’t use pass here then error message will be shown, print(‘my program'), OUTPUT, My program, Visit : python.mykvs.in for regular updates
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Iteration Statements (Loops), 3. pass Statement continue, e.g., for i in 'initial':, if(i == 'i'):, pass, else:, print(i), OUTPUT, n, t, a, L, , NOTE : continue forces the loop to start at the next iteration, while pass means "there is no code to execute here" and, will continue through the remainder or the loop body., Visit : python.mykvs.in for regular updates
