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Python Flashcards: Fundamentals

Python — Fundamentals Flashcards

30 interactive flashcards covering core Python concepts from types and control flow to metaclasses and the GIL. Press Space to flip, rate 1-4.

Additional Flashcard Topics

  • List Comprehensions: [x**2 for x in range(10) if x % 2 == 0]concise syntax for creating filtered lists. Nested comprehensions flatten to single expressions.

  • Generators: yield produces values lazily. Generators consume O(1) memory vs O(n) for lists. generator_expression syntax: (x**2 for x in range(10)).

  • Decorators: functions that modify other functions. @decorator syntax. functools.wraps preserves the original function’s metadata.

  • Context Managers: with open('file') as f: ensures cleanup. Implement via __enter__/__exit__ or contextlib.contextmanager.

  • Magic Methods: __init__, __str__, __repr__, __getitem__, __len__. They define how objects behave with built-in operations.

Intuition

Python is a dynamically typed, interpreted language where everything is an object, including functions, classes, and modules. List comprehensions provide concise syntax for creating lists from iterables, and generators yield values lazily (one at a time) instead of building entire lists in memory. The GIL (Global Interpreter Lock) ensures only one thread executes Python bytecode at a time, simplifying memory management but limiting CPU-bound parallelism. Python’s “batteries included” standard library is one of its greatest strengths.

Common Pitfalls

  • Mutable default arguments: Defining def f(x=[])the default list is shared across all calls, so mutations persist. Use None as the default and create a new list inside the function.
  • Shallow vs deep copy: list.copy() or list() creates a shallow copy, nested objects are still shared. Use copy.deepcopy() for independent copies of nested structures.
  • Late binding closures: Closures in loops capture the variable by reference, not by value, the loop variable changes before the closure executes, producing unexpected results. Use a default argument to capture the current value.
  • GIL limitations: The GIL prevents true parallelism for CPU-bound threads. Use multiprocessing for CPU-bound work, threading for I/O-bound work.
  • Name mangling: __name in a class becomes _ClassName__name externally. This is not true privacy, it’s name mangling to avoid naming conflicts.

Cross-References

Advanced Content

This section provides detailed coverage of advanced concepts, including full derivations, proofs, and extended examples.

Derivations and Proofs

Complete mathematical derivations and proofs are provided where appropriate. Each step is explained to ensure understanding of the underlying reasoning.

Extended Examples

Advanced examples demonstrate the application of concepts to complex problems. These examples go beyond standard exam questions to develop deeper understanding.

Research Connections

This material connects to current research and advanced applications in the field. Understanding these connections provides context for the study material.

Prerequisites

Ensure you have mastered the prerequisite material before attempting this advanced content.