An array stores elements in fixed-size, homogeneous positions. Python lists are the usual array-like choice, but they are variable-length and may hold different object types. section 4.5
Internally, a Python list is an array of pointers to Python objects. Python reserves spare capacity, reallocating and moving those pointers when the reserved space runs out, so appending can incur hidden overhead. section 4.5
Observe list capacity
Run the supplied measurement loop with sys.getsizeof. The reported size stays constant across several appends, then jumps as Python allocates a larger backing array.
Practice with array-like data
Write plus_minus([10, 20, 30, 40, 50, 60]) to compute 10+20-30+40-50+60, producing 50; then implement myzip for equal-length iterables. section 4.5
