Introduction to Python Programming - NMAM Institute of Technology PDF

Introduction To Python Programming CS1001-2 Course Outcomes: At the end of the course student will be able to 1. Understand and experiment with the basics of python programming like data types and looping. 2. Describe the concept of functions in python for solving real-world prob...

Introduction To Python Programming CS1001-2 Course Outcomes: At the end of the course student will be able to 1. Understand and experiment with the basics of python programming like data types and looping. 2. Describe the concept of functions in python for solving real-world problems. 3. Apply the Python operations for manipulating strings, lists, tuples and dictionaries. 4. Demonstrate the proficiency in handling File Systems. 5. Understand the basic knowledge on Exception handling and plotting graphs. Textbooks: 1. Kenneth A. Lambert, “The Fundamentals of Python: First Programs”, Cengage Learning, 2nd Edition, 2019. 2. Yashwanth Kanetkar, Adithya Kanetkar, “Let us Python”, 3rd Edition. 3. Mark Summerfield, “Programming in Python 3 - A Complete Introduction to the Python Language”, Second Edition, Addison-Wesley, 2009. 4. Y. Daniel Liang, “Introduction to Programming Using Python”, Pearson, 2013.  Unit -1 Introduction to Python and Function Chapter 1:Python Concepts Chapter 2: Design with functions What is python? Python is a very popular general-purpose interpreted, interactive, object- oriented, and high-level programming language. Why to learn python? Python is Open Source which means its available free of cost. Python is simple and so easy to learn Python is versatile and can be used to create many different things. Python has powerful development libraries include AI, ML etc. Prthviraj Jain, CSE Python is a widely used high-level, interpreted programming language. It was created by Guido van Rossum in 1991 and further developed by the Python Software Foundation Why the name python? Guido van Rossum was interested on watching a comedy show, which is telecasting on the BBC channel from 1969 to 1974 “The complete Monty Python‟s Flying Circus”. Guido Van Rossum thought he needed a name that was short, unique, and slightly mysterious for his programming language, so he decided to call the language Python. Key Features of Python Python is Easy to Learn and Use: There is no prerequisite to start Python, since it is Ideal programming language for beginners. High Level Language: Python don‟t let you worry about low-level details, like memory management, hardware-level operations etc. Python is Interpreted: Code is executed line-by-line directly by interpreter, and no need for separate compilation. Which means – You can run the same code across different platforms. You can make the changes in code without restarting the program. a) Demonstrate about Basics of Python Programming. Python comes with an interactive interpreter. When you type python in your shell or command prompt, the python interpreter becomes active with a >>> and waits for your commands. ii. Running Python Scripts in IDLE (Integrated Development and Learning Environment): IDLE is the standard Python development environment. It's name is an acronym of "Integrated DeveLopment Environment". It works well on both Unix and Windows platforms. It has a Python shell window, which gives you access to the Python interactive mode.  Goto File menu click on New File (CTRL+N) and write the code and save add.py iii. Running Python scripts in Command Prompt: Before going to run python27 folder in the command prompt. Open your text editor, type the following text and save it as hello.py. print "hello" In the command prompt, and run this program by calling python hello.py. Make sure you change to the directory where you saved the file before doing it. Python Identifier Python Identifier is the name we give to identify a variable, function, class, module or other object. That means whenever we want to give an entity a name, that‟s called identifier. Python Keywords Python keywords are the words that are reserved. That means you can‟t use them as name of any entities like variables, classes and functions. There were 33 keywords in Python 3.7. However, the number increased to 35 in Python 3.8. Keyword Description Keyword Description and A logical operator from To import specific parts of a module as To create an alias global To declare a global variable assert For debugging if To make a conditional statement break To break out of a loop import To import a module class To define a class in To check if a value is present in a list, tuple, etc. continue To continue to the next iteration of a loop is To test if two variables are equal def To define a function lambda To create an anonymous function del To delete an object None Represents a null value elif Used in conditional statements, same as else if nonlocal To declare a non-local variable else Used in conditional statements not A logical operator except Used with exceptions, what to do when an exception or A logical operator occurs False Boolean value, result of comparison operations pass A null statement, a statement that will do nothing finally Used with exceptions, a block of code that will be for To create a for loop Variable A variable, as the name indicates is something whose value is changeable over time. In fact a variable is a memory location where a value can be stored. Later we can retrieve the value to use. Python has no command for declaring a variable. A variable is created the moment you first assign a value to it. Example x=5 y = "John" print(x) print(y) No need to define type of variable. During the execution, the type of a variable is inferred from the context in which it is being used. Hence Python is called dynamically-typed language.  Simple variable assignment x=4 # x is of type int x = “nitte" # x is now of type str print(x) x = str(3) # x will be '3„ y = int(3) # y will be 3 z = float(3) # z will be 3.0 x=5 y = "John" print(type(x)) print(type(y)) Multiple variable assignment Rules for Writing Variable / Identifiers There are some rules for writing Identifiers. But first you must know Python is case sensitive. That means Name and name are two different identifiers in Python. Here are some rules for writing Identifiers in python. 1. Identifiers can be combination of uppercase and lowercase letters, digits or an underscore (_). So myVariable, variable_1, variable_for_print all are valid python identifiers. 2. An Identifier can not start with digit. So, while variable1 is valid, 1variable is not valid. 3. We can‟t use special symbols like !,#,@,%,$ etc in our Identifier. 4. Identifier can be of any length. Whether the following statement is true? x, y, z = “apple”, “banana”, “Cherry” print(x) print(y) print(z) Python Data Types Variables can store data of different types, and different types can do different things. Python has the following data types built-in by default, in these categories: 3 categories of data types: 1. Basic types: int, float, complex, bool, string, bytes Categories 2. Container types: list, tuple, set, dict Text Type: str 3. User-defined types: Class Numeric Types: int, float, complex Sequence Types: list, tuple, range Mapping Type: dict Boolean Type: bool Binary Types: bytes, bytearray None Type: NoneType  Data Types Basic type Container type User-defined type Numeric Types Text Type Boolean Type Binary Types Mapping Type Sequence Type class int String bool bytes dict list float tuple complex range  int can be expressed in binary, decimal, octal, hexadecimal. Integer type Starts with Example decimal 0-9 156 binary 0b/0B 0b101 octal 0o/0O 0o432 hexadecimal 0x/0X 0x443 int can be of any arbitrary size Python has arbitrary precision integers. Hence, we can create as big integers as we want. Arithmetic operations can be performed on integers without worrying about overflow/underflow.  float can be expressed in fractional or exponential form Eg: -314.1528, 3.141528e2, 3.141528E2 complex contains real and imaginary part 3+2j, 1+4J bool can take any of 2 Boolean values both starting in caps True, False string is an immutable collection of Unicode characters enclosed within „ „, “ “ or “”” “”” „hi‟, “hi”, “””hi””” bytes represent binary data B‟\xa1\xe4\x56‟ -represents 3bytes with hex value a1e456 Input and Output print()- used to output values on the screen input() built-in function can be used to retrieve input values from keyboard. input() function returns a string i.e if 23 is entered it returns ‟23‟ So to perform arithmetic operations on the number entered. Convert string to int or float. Operators Python divides the operators in the following groups: Arithmetic operators Assignment operators Comparison operators Logical operators Identity operators Membership operators Bitwise operators 1.Arithmetic operators Operator Name Example + Addition x+y - Subtraction x-y * Multiplication x*y / Division x/y % Modulus x%y ** Exponent x ** y // Floor division x // y Operation Nuances On performing floor division, a//b, result is largest integer which is less than or equal to the quotient. 2. Comparison Operators These are used to compare two operands. For example, compare the ages of two persons, compare the prices of two or more items, etc. They result in either a TRUE (Non-zero) value or FALSE (Zero) value Operator Name Example == Equal x == y != Not equal x != y > Greater than x>y < Less than x= Greater than or equal to x >= y >= x >>= 3 x = x >> 3 /= x /= 3 x=x/3