python minor Module I and II

Course Details

  • Course Code: CSC1MN102

  • Subject: Python Programming 1

  • Instructor: Dr Manjusha K K

  • Department: Department of Computer Application

  • Institution: Mar Dionysius College Pazhanji Thrissur

Introduction to Python Programming

  • Definition: A program is an ordered set of instructions executed by a computer to perform a specific task.

  • Programming Language: The language used to write this set of instructions.

  • Source Code: Programs written in high-level languages.

Translators

  • Interpreter vs Compiler:

    • Interpreter: Processes program statements one at a time, translating and executing consecutively; stops upon errors.

    • Compiler: Translates the entire source code into object code, generating error messages for encountered issues.

Python Virtual Machine

  • Role: The Python interpreter executes Python code, serving as an abstraction layer between Python bytecode and hardware.

Features of Python

  • High-level language, free and open-source.

  • Interpreted language, making it easy to use, case-sensitive, and portable.

  • Rich library providing numerous predefined functions.

Web Development

  • Python is widely used for developing web applications and services.

Writing and Executing Python Programs

Indentation

  • Python uses indentation to organize code blocks, which is essential for proper code execution and readability.

Running Python Programs

  • Interactive Mode: Execute single Python statements instantly at the prompt.

  • Script Mode: Write multiple instructions in a file with a .py extension for batch execution.

Comments in Python

  • Used for adding remarks in source code, which enhances code clarity.

  • Syntax: Starts with #, ignored by the interpreter.

Identifiers and Keywords

Identifiers

  • Names used for variables and functions.

  • Rules: Must start with a letter or underscore, can include letters, digits, and underscores. Cannot be a reserved word or start with a digit.

Keywords

  • Reserved words with specific meanings in Python.

Variables

  • Represents objects stored in memory, needing assignment before use.

  • Python allows implicit variable declaration; no explicit type definition is needed.

Example Code

# Area of a rectangle  
length = 10  
breadth = 20  
area = length * breadth  
print(area)  
# Output: 200

Everything is an Object

  • Python treats all data types as objects with unique identities.

  • Use id() function to return the identity of an object.

Data Types

  • Every value falls into a specific data type, identifying the kind of value it can hold and operations allowed.

  • Major categories include numbers, strings, lists, tuples, dictionaries, and sets.

Number Data Type

  • Types: Integer (int), Float (float), Complex (complex).

Sequences and Collections

  • Sequence: Ordered collection of items indexed by integers.

  • Types include:

    • String: Group of characters.

    • List: Items stored in square brackets [].

    • Tuple: Similar to lists but immutable.

Mapping

  • Dictionary: Holds key-value pairs, enabling rapid data access.

  • Access values using keys.

Input and Output

  • Use print() for output and input() for gathering user input.

Import Statements

  • Include external modules or libraries to extend functionality.

  • Syntax: import module_name or from module_name import item_name.

Example

import math  
print(math.sqrt(16))  # Output: 4.0

Range Function

  • Generates a sequence of numbers, commonly used for iterating in loops.

  • Syntax: range(start, stop, step) with optional parameters for range specification.

Operators

  • Types: Arithmetic, Assignment, Comparison, Logical, Identity, Membership, Bitwise.

Arithmetic Operators

  • Perform basic mathematical operations.

Assignment Operators

  • Assign values to variables.

Comparison Operators

  • Compare two values.

Logical Operators

  • Combine conditional statements.

Control Flow

  • Statements: Include if, elif, else, and nested structures.

Decision Making in Python

  • Built-in keywords: if, elif, else for conditional statements.

Syntax Example

if condition:  
    # execute block  
else:  
    # execute another block

Loops in Python

  • Types:

    • While Loop: Executes code block as long as condition is true.

    • For Loop: Iterates through a sequence or range.

    • Nested Loops: Loop inside another loop.

Control Statements

  • Break: Exits loop prematurely.

  • Continue: Skips current loop iteration.

  • Pass: Does nothing; a placeholder.

Nested Loops Example

for i in range(3):  
    for j in range(2):  
        print(i, j)

Conclusion

  • Understanding these foundational concepts is crucial for efficient Python programming and grasping more advanced topics.