README.md

Errors, Files, and Modules

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This section begins the transition from small in-memory programs to programs that must cope with failures, persistent data, and code organized across files.

Phase 7 starts with exception handling, then moves into deliberately raising exceptions, working safely with files and structured text data, and finally organizing Python code with imports, modules, and packages.

Learning path

Chapter	Main focus	Level	Status
01. try, except, else, and finally	Handle expected runtime failures while keeping normal and cleanup paths explicit	Beginner to intermediate	Available
02. Raising and Custom Exceptions	Signal invalid states deliberately with raise, re-raise or chain failures deliberately, and introduce simple custom exceptions	Intermediate	Available
03. open() and with	Open, read, write, and append text files while managing file resources safely with with	Beginner to intermediate	Available
04. TXT, CSV, and JSON	Parse, write, convert, and validate common text-based data formats with format-aware tools	Intermediate	Available
05. Imports, Modules, and Packages	Split code into reusable files, organize regular packages, and understand Python's import and execution context	Intermediate	Available

Prerequisite guidance

Before starting this phase, learners should be comfortable with:

• conditions and Boolean logic;
• loops;
• functions, parameters, and return values;
• basic type conversion;
• reading simple tracebacks conceptually;
• the difference between source-code comments and runtime behavior.

The complete beginner path through Phases 1–6 provides all of these foundations.

Recommended sequence

Study the chapters in numerical order when following the complete curriculum:

01. Handle exceptions
        ↓
02. Raise exceptions deliberately
        ↓
03. Open and manage files
        ↓
04. Read and write common data formats
        ↓
05. Organize code with modules and packages

The sequence is intentional. Before a program starts depending on files and multiple modules, it should have a clear model for what happens when an operation cannot complete normally.

Section goals

By the end of Phase 7, you should be able to:

• distinguish normal control flow from exception-driven control flow;
• handle specific runtime exceptions without hiding unrelated failures;
• use else and finally deliberately;
• raise appropriate exceptions when a function cannot honor its contract;
• open, read, and write files using safe resource-management patterns;
• work with plain text, CSV, and JSON at a beginner-friendly level;
• separate parsing, validation, transformation, and persistence responsibilities;
• import code from modules and packages;
• explain how files, exceptions, functions, and modules connect in a small real program.

Phase status

Phase 7 is complete. Finish the section with Organizing Code with Imports, Modules, and Packages.

Chapters 01–02 establish exception handling and deliberate exception signaling. Chapter 03 adds safe text-file lifetime and I/O. Chapter 04 adds TXT, CSV, and JSON data boundaries. Chapter 05 closes the phase with explicit imports, modules, regular packages, __name__, the main guard, search context, relative imports, python -m, and dependency design.

Directory structure

errors-files-and-modules/
├── README.md
├── README.pt-BR.md
├── README.es.md
├── 01-try-except-else-finally/
│   ├── README.md
│   ├── README.pt-BR.md
│   ├── README.es.md
│   └── examples/
│       ├── parse_integer.py
│       ├── safe_divide.py
│       └── trace_try_else_finally.py
├── 02-raise-and-custom-exceptions/
│   ├── README.md
│   ├── README.pt-BR.md
│   ├── README.es.md
│   └── examples/
│       ├── custom_exception.py
│       ├── exception_chaining.py
│       └── validate_score.py
├── 03-open-and-with/
│   ├── README.md
│   ├── README.pt-BR.md
│   ├── README.es.md
│   └── examples/
│       ├── append_text.py
│       ├── handle_missing_file.py
│       └── write_and_read_text.py
├── 04-txt-csv-and-json/
│   ├── README.md
│   ├── README.pt-BR.md
│   ├── README.es.md
│   └── examples/
│       ├── csv_records.py
│       ├── handle_invalid_json.py
│       ├── json_document.py
│       └── text_records.py
└── 05-imports-modules-and-packages/
    ├── README.md
    ├── README.pt-BR.md
    ├── README.es.md
    └── examples/
        ├── grade_tools.py
        ├── import_standard_library.py
        ├── main_guard.py
        ├── module_demo.py
        ├── package_demo.py
        └── study_tools/
            ├── __init__.py
            └── formatting.py

All five planned Phase 7 chapter directories are now published.