Computers and Python Introduction

Chapter 1: Introduction to Computers, Programs, and Python

• Python is a popular, open-source programming language used for various applications.
• It's free, portable, powerful, and user-friendly.
• Developers across the software industry find Python's efficiency and quality beneficial for large and small projects.
• The book aims to quickly teach fundamental core Python language concepts.

What is a Computer?

• A computer comprises hardware (visible physical parts) and software (invisible instructions).
• Hardware components include:
  • Central Processing Unit (CPU)
  • Memory (main memory)
  • Storage devices (disks, CDs)
  • Input devices (mouse, keyboard)
  • Output devices (monitors, printers)
  • Communication devices (modems, network cards)

Programming Languages

• Computers do not understand human languages, so programming languages are required.
• Numerous programming languages exist; each designed for a specific purpose.
• All programs need translation into a language the computer can understand.

Machine Language

• Machine language is a computer's native language.
• It varies between computer types.
• It contains built-in primitive instructions.
• Instructions are in binary code. For example, an instruction to add two numbers may appear as 1101101010011010

High-Level Language

• High-level languages are created to simplify programming.

• Table 1 lists several popular high-level languages.

  • Ada: Main use in defense projects
  • BASIC: Beginner-friendly language
  • C: Combines assembly and high-level features, high portability
  • C++: Object-oriented, based on C
  • C#: Microsoft's hybrid language that combines Java and C++
  • COBOL: Primarily for business applications;
  • FORTRAN: Scientific and mathematical calculations.
  • Java: Platform-independent for internet applications
  • Pascal: Simple, useful for teaching programming
  • Python: General-purpose scripting language; used for short programs and Windows applications
  • Visual Basic: Microsoft language for rapid development of Windows applications

• A source program is a program written in a high-level language.

• A compiler translates a whole source program into a machine language file, then executes it.

• An interpreter translates and executes one statement at a time.

Getting Started with Python

• Python is a popular, high-level, easy-to-learn programming language.
• It's open source.
• Syntax is clear and easy to understand for quick readability.
• A large, comprehensive standard library.

The Problem Analysis–Coding–Execution Cycle

• Steps to get output from Python code involve:
  • Problem analysis
  • Algorithm design
  • Coding
  • Compilation
  • Translating to Machine Language
  • Execution
  • Error checking
  • Results collection

How to Download and Install Python

• Download Python via web browser to the relevant version for your operating system.
• Install the downloaded file.
• Add Python installation directory to PATH (environment variable).
• Verify Python installation by opening IDLE.

Python Tools for Development

• Python has libraries and compilers (Python 3)
• Other tools are available (e.g., Atom, Sublime, Notepad++, IDLE, Jupyter, PyCharm, Thonny, Spyder)

Creating Python Source Code Files

• To save and reuse Python statements, create a text file.
• Conventionally, save files with the extension.py
• Python source file (or script file/module) written by a text file.
• Running from a file is called script mode.
• Entering statements directly is called interactive mode.
• Comments begin with #.

Python Special Characters

• Table 2 summarizes the use of special characters(e.g., (), #, "").

Programming Errors

• Errors in Python programming fall into three types:
  • Syntax errors
  • Runtime errors
  • Logic errors

End of Chapter Questions

• Examples of quiz-style problems. Example questions are provided, but not answered.