Topic_1__-_Introduction

Introduction to CSPG1205 Programming Python

• Outcome #1: Define computer programming concepts.

What is a Computer Program?

• A program is a sequence of instructions specifying how to perform a computation.

• Computations can be categorized into:

  • Mathematical: Solving equations.

  • Symbolic: Searching/replacing text in a document.

  • Graphical: Processing images or videos, and more.

Why Should You Learn to Write Programs?

• Problem solving is crucial for computer scientists:

  • It involves formulating problems, thinking creatively about solutions, and expressing these solutions clearly.

  • Learning to write computer programs provides an excellent opportunity to practice these skills.

• Example Problem: To find speed during a journey:

  • Know distance.

  • Know time.

  • Divide distance by time to find speed.

  • Display the speed result.

Languages

• Definition: A language is a tool to express and record thoughts.

• Machine Language: The computer's own language.

• Natural Language: Human languages; a common language for humans and computers is necessary.

Programming Languages

• A programming language is a formal language used to create computer programs.

• Examples of programming languages:

  • Python

  • C++

  • JavaScript

  • Scala

  • Java

  • PHP

  • Ruby

  • C#

Programmer

• A programmer is someone skilled in programming.

• Responsibilities include:

  • Writing source code for applications.

  • Testing, maintaining, and debugging software applications.

Building Blocks of Programs

• Input: Acquiring data from external sources (keyboard, files, sensors).

• Output: Displaying results or storing them (e.g., on a screen or in a file).

• Execution Types:

  • Sequential execution: Running statements one after another.

  • Conditional execution: Executing or skipping statements based on certain conditions.

  • Repeated execution: Running a set of statements multiple times, with variations.

  • Reuse: Creating named instructions for recurring use throughout the program.

About Python

• General Characteristics:

  • Easy to learn.

  • Widely used in various organizations (e.g., Google, NASA, Yahoo).

  • Created by Guido van Rossum in 1991.

  • Named after “Monty Python’s Flying Circus.”

Companies Using Python

• Notable companies include:

  • Nokia

  • Amazon

  • Dropbox

  • Reddit

  • Yahoo!

  • IBM

  • Quora

  • Disney

  • Netflix

Advantages of Python

• Simplicity and Power:

  • Efficient high-level data structures.

  • Object-oriented programming capabilities.

• Characteristics:

  • Interpreted language with dynamic semantics.

  • High-level language: No need to manage memory.

  • Portable across platforms without changes.

Features of Python

• Simple and Minimalistic Language:

  • Easy to learn and has an intuitive syntax.

• Free and Open Source:

  • Can be freely distributed and modified.

• Interpreted Language:

  • Runs programs directly from source code by converting into bytecodes and then running on the native mode.

• Object-Oriented:

  • Supports both procedural and object-oriented programming, enabling code reuse and reducing complexity.

Object-Oriented vs. Procedure-Oriented Programming

• Procedure-Oriented Language:

  • Centers around procedures or functions, executing commands in a specific order, facilitating code reuse.

• Object-Oriented Language:

  • Focuses on objects combining data and functionalities, reflecting real-world interactions.

Extensibility and Embedding

• Extensible:

  • Critical pieces of code can be written in fast languages (e.g., C/C++) and called from Python.

• Embedded:

  • Python can be integrated within C/C++ programs for scripting capabilities.

Extensive Libraries

• Python has a vast Standard Library assisting with:

  • Regular expressions, multi-threading, databases, web browsers, HTML, GUI development, etc.

Interpreter and Compiler

• Machine Language:

  • Comprised of zeros and ones (binary), specific to hardware and not portable.

• High-Level Language:

  • Python is user-friendly for reading and writing, contrasting with machine language.

• Types of Translators:

  • Interpreters: Read source code and execute on the fly.

  • Compilers: Convert entire source code to machine language at once.

Terminology: Interpreter vs. Compiler

• Interpreter:

  • Processes Python code instantly, allowing immediate response in an interactive setting.

• Compiler:

  • Translates source code into machine language, creating files for later execution.

Example: Hello World Program in Python

• Written in three lines:

  • Line 1: Comment indicating program start (#).

  • Line 2: print(“Hello world!”) function to output text.

  • Line 3: Comment indicating program end (#).

Python Programming Environment: Jupyter Notebooks

• Features:

  • Enables creation and execution of interactive programs in a single document.

  • Accessible through a web browser with features for direct sharing and visualization.

Anaconda Navigator

• Applications:

  • Includes Jupyter Notebook, JupyterLab, Spyder (IDE) for Python development.

Working with Jupyter Notebooks

• Creating a New Notebook:

  • Accessible via the 'New' button in the Jupyter interface for Python 3.

Notebook Structure and Cells

• Notebook Cells:

  • Comprised of various cell types:

    • Code Cell: Contains executable code.

    • Markdown Cell: Contains formatted text.

    • Raw Cell: Displays content without processing.

Notebook Tips

• To execute cells:

  • Select and press shift + enter or ctrl + enter.

  • Options to run all cells or specific ones.

  • Features for adding, deleting, and reordering cells.

  • Supports saving and downloading in various formats (.ipynb, .py, .pdf, .html).

References

• Learning resources:

  • Severance C. R. (2016). Python for Everybody.

  • Swaroop C.H. (2013). A Byte of Python.

  • Downey A.B. (2016). Think Python.

  • Romano F. (2018). Learn Python Programming.