iters.py

View source code here on GitHub!

Includes

python.src.lib.iters.abundants(stop: int | None = None) → Iterator[int]

Iterate over the abundant numbers.

python.src.lib.iters.consume(iterator: Iterable[Any], n: int | None = None) → None

Advance the iterator n-steps ahead. If n is None, consume entirely. (From itertools recipes)

python.src.lib.iters.digits(x: int, base: int = 10) → Iterator[int]

Iterate over the digits of a number in a given base.

python.src.lib.iters.groupwise(iterable: Iterable[T], size: int) → Iterator[Tuple[T, ...]]

Iterate over something in buckets of a given size.

python.src.lib.iters.spiral_corners(i: int) → Tuple[int, int, int, int]
 1from __future__ import generator_stop
 2
 3from collections import deque
 4from itertools import count, islice, tee
 5from typing import Any, Iterable, Iterator, Optional, Tuple, TypeVar
 6
 7from .factors import proper_divisors
 8
 9T = TypeVar("T")
10
11
12def abundants(stop: Optional[int] = None) -> Iterator[int]:
13    """Iterate over the abundant numbers."""
14    if stop is None:
15        iterator: Iterable[int] = count(12)
16    else:
17        iterator = range(12, stop)
18    for x in iterator:
19        if sum(proper_divisors(x)) > x:
20            yield x
21
22
23def consume(iterator: Iterable[Any], n: Optional[int] = None) -> None:
24    "Advance the iterator n-steps ahead. If n is None, consume entirely. (From itertools recipes)"
25    # Use functions that consume iterators at C speed.
26    if n is None:
27        deque(iterator, maxlen=0)
28    else:
29        next(islice(iterator, n, n), None)
30
31
32def digits(x: int, base: int = 10) -> Iterator[int]:
33    """Iterate over the digits of a number in a given base."""
34    while x:
35        x, y = divmod(x, base)
36        yield y
37
38
39def groupwise(iterable: Iterable[T], size: int) -> Iterator[Tuple[T, ...]]:
40    """Iterate over something in buckets of a given size."""
41    iters = tee(iterable, size)
42    for idx, x in enumerate(iters):
43        for _ in range(idx):
44            next(x, None)
45    return zip(*iters)
46
47
48def spiral_corners(i: int) -> Tuple[int, int, int, int]:
49    r = range((2 * i - 1)**2 + 1, (2 * i + 1)**2 + 1)
50    return (
51        r[1 * 2 * i - 1],
52        r[2 * 2 * i - 1],
53        r[3 * 2 * i - 1],
54        r[4 * 2 * i - 1]
55    )

Tags: python-iterator