Mutable Default Arguments in Python
Why Python evaluates default arguments once, how mutable defaults retain state between calls, and how the None sentinel pattern avoids the problem.
Python
3 articles
Understanding Python's Object Model, Part 1
An introduction to CPython's object representation through PyObject, PyVarObject, reference counting, type pointers, and variable-sized objects.
Efficient Factorial Algorithms
A comparison of recursive, iterative, paired-multiplication, and prime-decomposition approaches to computing large factorials in Python and Java.