Introduction To Python: 11th Computer Science Chapter 01

Chapter Name:	Introduction To Python [Chapter 01]
Class:	11th
Subject:	Computer Science

1.1 Introduction:

• General-purpose Object Oriented Programming language.
• High-level language
• Developed in late 1980 by Guido van Rossum at National Research Institute for Mathematics and Computer Science in The Netherlands.
• It is derived from programming languages such as ABC, Modula 3, small talk, Algol68.
• It is Open Source Scripting language.
• It is Case-sensitive language (Difference between uppercase and lowercase letters).
• One of the official languages at Google.

1.2 Characteristics of Python:

• Interpreted: Python source code is compiled to byte code as a .pyc file, and this byte code can be interpreted by the interpreter.
• Interactive
• Object Oriented Programming Language
• Easy & Simple
• Portable
• Scalable: Provides improved structure for supporting large programs.
• Integrated
• Expressive Language

1.3 Python Interpreter:

Names of some Python interpreters are:

• PyCharm
• Python IDLE
• The Python Bundle
• pyGUI
• Sublime Text etc.

Interactive Mode:

Without passing python script file to the interpreter, directly execute code to Python (Command line).

Example:
>>> 6+3
Output: 9

Note: >>> is a command the python interpreter uses to indicate that it is ready. The interactive mode is better when a programmer deals with small pieces of code.

To run a python file on command line:

exec(open(“C:\Python33\python programs\program1.py”).read( ))

Script Mode:

In this mode source code is stored in a file with the .py extension and use the interpreter to execute the contents of the file. To execute the script by the interpreter, you have to tell the interpreter the name of the file.

Example:

If you have a file name Demo.py, to run the script you have to follow the following

Steps:

Step 1: Open the text editor i.e. Notepad
Step 2: Write the python code and save the file with .py file extension. (Default directory is C:\Python33/Demo.py)
Step 3: Open IDLE ( Python GUI) python shell
Step 4: Click on file menu and select the open option
Step 5: Select the existing python file
Step 6: Now a window of python file will be opened
Step 7: Click on Run menu and the option Run Module.
Step 8: Output will be displayed on python shell window.