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Welcome to Brad’s Python Notes (PyNotes!).
This is Brad’s Python Notes - a blog covering interesting aspects about Python, covering the Python Tutorial, the Python Standard Libraries and the Python Enhancement Proposals (PEPs).
Recent posts
Context Managers: Mastering Python's Resource Management
TL;DR
Context managers handle setup and cleanup automatically using the
withstatement, implementing__enter__and__exit__methods to guarantee resource cleanup even when exceptions occur.PEP 448: Additional Unpacking Generalizations
TL;DR
PEP 448 extended Python’s unpacking operators (
*and**) in Python 3.5, allowing multiple unpackings in function calls and enabling unpacking directly within list, tuple, set, and dictionary literals. This eliminates verbose workarounds and makes code more concise and readable.Built-in Exceptions
TL;DR
Python’s built-in exceptions form a strict inheritance hierarchy rooted in
BaseException, with all user code exceptions inheriting fromException. Choose specific exception types likeValueError(wrong value) orTypeError(wrong type) rather than generic exceptions, and consider carefully before catchingBaseExceptionin user code as it will do things like capture keyboard interrupts (no Ctrl-C for you!).Codecs Module: Mastering Text Encoding and Decoding
TL;DR
The codecs module provides functions to encode and decode data between bytes and text using various character encodings (UTF-8, ASCII, etc.), with flexible error handling strategies for dealing with malformed data.
Tutorial: Errors and Exceptions
TL;DR
Python separates syntax errors (caught before running) from exceptions (caught during execution). The try/except/finally system lets you catch errors, recover gracefully, and guarantee cleanup code runs.
Difflib Module
TL;DR
The
difflibmodule provides tools for comparing sequences (especially text strings) and generating difference reports in various formats. It can find the similarity between strings, produce unified or context diffs like Unix diff tools, and identify close matches from a list of possibilities.PEP 621: Storing Project Metadata in pyproject.toml
TL;DR
PEP 621 established a standardized
[project]table inpyproject.tomlfor declaring Python project metadata. It provided a tool-agnostic, static format that replaced executablesetup.pycode and tool-specificsetup.cfgfiles with declarative TOML that could be parsed without running code.PEP 3105: Make print a Function
TL;DR
PEP 3105 converted Python’s
printstatement into a built-in function in Python 3.0. This change provided consistency with the rest of Python’s syntax and allowed features like custom separators, file output redirection, and easy replacement with logging systems.PEP 257: Docstring Conventions for Self-Documenting Code
TL;DR
PEP 257 defines standardized conventions for Python docstrings, covering how to document modules, functions, classes, and methods using string literals that become the
__doc__attribute. The conventions emphasize triple double quotes, command-style phrasing, and consistent formatting.PEP 3134: Exception Chaining and Embedded Tracebacks
TL;DR
PEP 3134 introduced exception chaining in Python 3, allowing exceptions to preserve their context when new exceptions occur during error handling. The
raise ... fromsyntax creates explicit chains, while Python automatically captures implicit chains, both appearing in tracebacks to simplify debugging.