Basic Primitive Idea - From Chapter 3 (NCERT) for IP students, CBSE

1. Basics of Python
Programming
-By Aditi Bhushan
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2. UNIT – 2: PYTHON [REVISED SYLLABUS]
• TOTAL = 25/100
• Basics of Python programming,
• Python interpreter - interactive and script
mode,
• the structure of a program,
• indentation,
• identifiers, keywords, constants, variables,
• types of operators, precedence of operators,
• data types, mutable and immutable data
types,
• statements, expressions, evaluation and
comments, input and output statements
• data type conversion,
• debugging.
• Control Statements: if-else, for loop
• Lists: list operations - creating,
initializing, traversing and
manipulating lists, list methods and
built-in functions.
• Dictionary: concept of key-value pair,
creating, initializing, traversing,
updating and deleting elements,
dictionary methods and built-in
functions.
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3. Introduction to Python
Version Python 3 or Python 3.7.0 or Latest Version: Python 3.8.5
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4. Why Python? (for understanding purpose, not
for evaluation)
• Powerful Language
• Supports “Scripting Language”
• Concise Formatting Style of Language
• Every Value is an Object.
• Supports iteration and abstractions – thereby making
generics easy with dynamic typing
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5. Language Features (for understanding
purpose, not for evaluation)
• Supports Indentation instead of braces
• Powerful subscripting (slicing)
• Functions are independent entities (not all functions are methods)
• Exceptions as in Java
• Simple object system
• Iterators (like Java) and generators
• Several sequence types
• Strings ’…’: made of characters, immutable
• Lists […]: made of anything, mutable
• Tuples (…) : made of anything, immutable
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6. Basics of Python
• Created by Guido van Rossum in 1991
• Object Oriented Programming
• Uses: software development, web development, scientific computing,
big data and artificial intelligence
• Download Latest Version of Python IDE from:
https://www.python.org/
• Online Editor for Python:
https://www.onlinegdb.com/online_python_compiler
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7. Installation
• Python is pre-installed on most Unix systems,
including Linux and MAC OS X
• Python comes with a large library of standard modules
• There are several options for an IDE
• IDLE – works well with Windows
• Emacs with python-mode or your favorite text editor
• Eclipse with PyDev (http://pydev.sourceforge.net/ )
• PyCharm (https://www.jetbrains.com/pycharm/)
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8. Starting with Python
Installation Steps (Please Find attached the Pics)
1. Put a tick mark on Add Path
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9. 2. Change Custom Path (Optional)
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10. IDLE Development Environment
• IDLE is an Integrated DeveLopment Environment for Python, typically
used on Windows
• Multi-window text editor with
• syntax highlighting,
• auto-completion,
• smart indention
• Integrated debugger with
• stepping,
• persistent breakpoints,
• call stack visibility
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11. Windows IDLE
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To write and run (execute) a Python program, we need to have a
✓ Python interpreter installed on our computer or
✓ any online Python interpreter. The interpreter is also called Python shell.
Python Interpreter
Here, the symbol >>> is called Python prompt, which indicates that the
interpreter is ready to receive instructions.

12. Execution Modes
INTERACTIVE MODE
• Single line code for instant
execution.
• Good for beginners at starting.
• We cannot save the statements for
further use.
SCRIPT MODE
• Python Program/Scripts are written
and saved with .py extension.
• Good for bigger programs or
professionals.
• We can Save and Reuse them.
Consist of built-in editors known as
IDLE.
• By default, the Python scripts are
saved in the Python installation
folder.
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13. COMMENTS
• Start comments with #, rest of line is ignored
• Can include “string” as the first line of a new function.
• Development environments, debugger, and other tools use it: it’s
good style to include one
def fact(n):
“““fact(n) assumes n is a positive integer and
returns factorial of n.”””
assert(n>0)
return 1 if n==1 else n*fact(n-1)
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