Intro to Python

Words and Sentences in Python

• Python Reserved Words:

  • Python has a small set of reserved words that hold special meanings (e.g., if, else, for), which cannot be used as variable names.

  • Example of valid syntax: print('Hello world!').

Conversing with Python

• Engaging with Python:

  • Python operates in an interactive mode where you can execute commands directly (prompted by >>>).

  • Errors in syntax (e.g., primt 'Hello world!') indicate issues needing correction.

  • Proper exit command is quit().

Terminology: Interpreter and Compiler

• High-Level vs Low-Level Languages:

  • High-level languages (e.g., Python) are designed for human ease of use, while low-level languages (e.g., machine code) are suited for direct CPU execution.

• Interpreters and Compilers:

  • Interpreter: Processes code line-by-line, making it easier to test and debug interactively.

  • Compiler: Translates the entire program into machine code for execution in a non-interactive mode.

Writing a Program

• Script Development:

  • Python programs are commonly written in text files (scripts), which are conventionally named with a .py extension.

  • Example shell command: python hello.py executes a script named hello.py.

Building Blocks of Programs

• Basic Constructs:

  • Input/Output, Sequential Execution, Conditional Execution, Repeated Execution, Reuse:

  • Programs utilize these constructs to process data and produce results.

Debugging and Error Types

• Types of Errors:

  • Syntax Errors: Incorrect grammar in code; easiest to fix.

  • Logic Errors: Correct syntax but incorrect program flow; often requires a deeper understanding of program logic.

  • Semantic Errors: Code that runs without errors but produces unexpected results; a misunderstanding of functionality.

The Learning Journey

• Conceptual Progression:

  • Learning programming is similar to acquiring a language; it develops over time and requires practice.

  • Strategies for overcoming challenges include stepping back, taking breaks, and engaging with peers for discussions.