Python Institute PCAP Course Notes

Know exactly what an import binds, how Python resolves module names, and the PCAP-specific standard-library calls in `math`, `random`, and `platform`. Be able to reason about `__name__`, `__all__`, leading underscores, `__pycache__`, conventional packages, and search-path shadowing.

• Treating `ceil()` as 'away from zero' for negative numbers.

• For imports, write down the exact name that appears in the current namespace.

Trace exception flow precisely. Know handler order and hierarchy, `as exc`, grouped handlers, `.args`, `else`, `finally`, explicit and bare `raise`, `raise ... from ...`, assertions, and custom exception inheritance.

• Putting a broad base-class handler before a specific subclass handler.

• Before tracing, identify the exact exception class raised.

Master the distinction between characters, Unicode code points, and encoded bytes; then trace Python string operations and method return behavior exactly. Most misses come from immutability, slice boundaries, `ord`/`chr`, classification methods, and `find` versus `index`.

• Treating code points and UTF-8 bytes as the same thing.

• Track both value and type when encoding, decoding, sorting, or calling `ord`/`chr`.

This is the largest PCAP domain. Trace Python's object model: instance versus class state, attribute lookup, methods and binding, introspection, inheritance/MRO/polymorphism, identity, constructors, and initialization. Expect many short code-tracing questions.

• Assuming changing one instance attribute changes the class attribute.

• For every attribute expression, ask: instance dictionary first, then class/inheritance lookup?

Trace compact Python constructs accurately: list comprehensions, lambdas, `map`/`filter`, closures, and file I/O. Know iterator behavior, closure binding/state, stream terminology, text-versus-binary types, file modes, stream position, and mutable `bytearray`.

• Confusing a comprehension filter with a conditional expression.

• When confused by a comprehension, rewrite it as ordinary nested `for` statements.