PYTHON PROGRAMMING III YEAR/II SEM MRCET
UNIT – I
INTRODUCTION DATA, EXPRESSIONS, STATEMENTS
Introduction to Python and installation, data types: Int, float, Boolean, string, and list;
variables, expressions, statements, precedence of operators, comments; modules, functions--
- function and its use, flow of execution, parameters and arguments.
Introduction to Python and installation:
Python is a widely used general-purpose, high level programming language. It was initially
designed by Guido van Rossum in 1991 and developed by Python Software Foundation. It
was mainly developed for emphasis on code readability, and its syntax allows programmers
to express concepts in fewer lines of code.
Python is a programming language that lets you work quickly and integrate systems more
efficiently.
There are two major Python versions- Python 2 and Python 3.
• On 16 October 2000, Python 2.0 was released with many new features.
• On 3rd December 2008, Python 3.0 was released with more testing and includes new
features.
Beginning with Python programming:
1) Finding an Interpreter:
Before we start Python programming, we need to have an interpreter to interpret and run our
programs. There are certain online interpreters like https://ide.geeksforgeeks.org/,
http://ideone.com/ or http://codepad.org/ that can be used to start Python without installing
an interpreter.
Windows: There are many interpreters available freely to run Python scripts like IDLE
(Integrated Development Environment) which is installed when you install the python
software from http://python.org/downloads/
2) Writing first program:
# Script Begins
Statement1
1
,PYTHON PROGRAMMING III YEAR/II SEM MRCET
Statement2
Statement3
# Script Ends
Differences between scripting language and programming language:
Why to use Python:
The following are the primary factors to use python in day-to-day life:
1. Python is object-oriented
Structure supports such concepts as polymorphism, operation overloading and
multiple inheritance.
2. Indentation
Indentation is one of the greatest feature in python
2
,PYTHON PROGRAMMING III YEAR/II SEM MRCET
3. It’s free (open source)
Downloading python and installing python is free and easy
4. It’s Powerful
Dynamic typing
Built-in types and tools
Library utilities
Third party utilities (e.g. Numeric, NumPy, sciPy)
Automatic memory management
5. It’s Portable
Python runs virtually every major platform used today
As long as you have a compaitable python interpreter installed, python
programs will run in exactly the same manner, irrespective of platform.
6. It’s easy to use and learn
No intermediate compile
Python Programs are compiled automatically to an intermediate form called
byte code, which the interpreter then reads.
This gives python the development speed of an interpreter without the
performance loss inherent in purely interpreted languages.
Structure and syntax are pretty intuitive and easy to grasp.
7. Interpreted Language
Python is processed at runtime by python Interpreter
8. Interactive Programming Language
Users can interact with the python interpreter directly for writing the programs
9. Straight forward syntax
The formation of python syntax is simple and straight forward which also makes it
popular.
Installation:
There are many interpreters available freely to run Python scripts like IDLE (Integrated
Development Environment) which is installed when you install the python software
from http://python.org/downloads/
Steps to be followed and remembered:
Step 1: Select Version of Python to Install.
Step 2: Download Python Executable Installer.
Step 3: Run Executable Installer.
Step 4: Verify Python Was Installed On Windows.
3
, PYTHON PROGRAMMING III YEAR/II SEM MRCET
Step 5: Verify Pip Was Installed.
Step 6: Add Python Path to Environment Variables (Optional)
Working with Python
Python Code Execution:
Python’s traditional runtime execution model: Source code you type is translated to byte
code, which is then run by the Python Virtual Machine (PVM). Your code is automatically
compiled, but then it is interpreted.
Source Byte code Runtime
PVM
m.py m.pyc
Source code extension is .py
Byte code extension is .pyc (Compiled python code)
There are two modes for using the Python interpreter:
• Interactive Mode
• Script Mode
4
UNIT – I
INTRODUCTION DATA, EXPRESSIONS, STATEMENTS
Introduction to Python and installation, data types: Int, float, Boolean, string, and list;
variables, expressions, statements, precedence of operators, comments; modules, functions--
- function and its use, flow of execution, parameters and arguments.
Introduction to Python and installation:
Python is a widely used general-purpose, high level programming language. It was initially
designed by Guido van Rossum in 1991 and developed by Python Software Foundation. It
was mainly developed for emphasis on code readability, and its syntax allows programmers
to express concepts in fewer lines of code.
Python is a programming language that lets you work quickly and integrate systems more
efficiently.
There are two major Python versions- Python 2 and Python 3.
• On 16 October 2000, Python 2.0 was released with many new features.
• On 3rd December 2008, Python 3.0 was released with more testing and includes new
features.
Beginning with Python programming:
1) Finding an Interpreter:
Before we start Python programming, we need to have an interpreter to interpret and run our
programs. There are certain online interpreters like https://ide.geeksforgeeks.org/,
http://ideone.com/ or http://codepad.org/ that can be used to start Python without installing
an interpreter.
Windows: There are many interpreters available freely to run Python scripts like IDLE
(Integrated Development Environment) which is installed when you install the python
software from http://python.org/downloads/
2) Writing first program:
# Script Begins
Statement1
1
,PYTHON PROGRAMMING III YEAR/II SEM MRCET
Statement2
Statement3
# Script Ends
Differences between scripting language and programming language:
Why to use Python:
The following are the primary factors to use python in day-to-day life:
1. Python is object-oriented
Structure supports such concepts as polymorphism, operation overloading and
multiple inheritance.
2. Indentation
Indentation is one of the greatest feature in python
2
,PYTHON PROGRAMMING III YEAR/II SEM MRCET
3. It’s free (open source)
Downloading python and installing python is free and easy
4. It’s Powerful
Dynamic typing
Built-in types and tools
Library utilities
Third party utilities (e.g. Numeric, NumPy, sciPy)
Automatic memory management
5. It’s Portable
Python runs virtually every major platform used today
As long as you have a compaitable python interpreter installed, python
programs will run in exactly the same manner, irrespective of platform.
6. It’s easy to use and learn
No intermediate compile
Python Programs are compiled automatically to an intermediate form called
byte code, which the interpreter then reads.
This gives python the development speed of an interpreter without the
performance loss inherent in purely interpreted languages.
Structure and syntax are pretty intuitive and easy to grasp.
7. Interpreted Language
Python is processed at runtime by python Interpreter
8. Interactive Programming Language
Users can interact with the python interpreter directly for writing the programs
9. Straight forward syntax
The formation of python syntax is simple and straight forward which also makes it
popular.
Installation:
There are many interpreters available freely to run Python scripts like IDLE (Integrated
Development Environment) which is installed when you install the python software
from http://python.org/downloads/
Steps to be followed and remembered:
Step 1: Select Version of Python to Install.
Step 2: Download Python Executable Installer.
Step 3: Run Executable Installer.
Step 4: Verify Python Was Installed On Windows.
3
, PYTHON PROGRAMMING III YEAR/II SEM MRCET
Step 5: Verify Pip Was Installed.
Step 6: Add Python Path to Environment Variables (Optional)
Working with Python
Python Code Execution:
Python’s traditional runtime execution model: Source code you type is translated to byte
code, which is then run by the Python Virtual Machine (PVM). Your code is automatically
compiled, but then it is interpreted.
Source Byte code Runtime
PVM
m.py m.pyc
Source code extension is .py
Byte code extension is .pyc (Compiled python code)
There are two modes for using the Python interpreter:
• Interactive Mode
• Script Mode
4
