Source code for faust.utils.functional

"""Functional utilities."""
from functools import reduce
from itertools import groupby
from typing import (
    Iterable,
    Iterator,
    Mapping,
    Optional,
    Sequence,
    Tuple,
    TypeVar,
)
from mode.utils.typing import Deque

__all__ = [
    'consecutive_numbers',
    'deque_prune',
    'deque_pushpopmax',
    'translate',
]

T = TypeVar('T')


[docs]def consecutive_numbers(it: Iterable[int]) -> Iterator[Sequence[int]]: """Find runs of consecutive numbers. Notes: See https://docs.python.org/2.6/library/itertools.html#examples """ for _, g in groupby(enumerate(it), lambda a: a[0] - a[1]): yield [a[1] for a in g]
[docs]def deque_prune(l: Deque[T], max: int = None) -> Optional[T]: """Prune oldest element in deque if size exceeds ``max``.""" if max is not None: size = len(l) if size > max: return l.popleft() return None
[docs]def deque_pushpopmax(l: Deque[T], item: T, max: int = None) -> Optional[T]: """Append to deque and remove oldest element if size exceeds ``max``.""" l.append(item) return deque_prune(l, max)
[docs]def translate(table: Mapping, s: str) -> str: """Replace characters and patterns in string ``s``. Works similar to :meth:`str.translate`, but replacements and patterns can be full length strings instead of character by character. Arguments: table: A mapping of characters/patterns to their replacement string. s: The string to translate Note: Table is the first argument in the signature for compatibility with :func:`~functools.partial`: .. sourcecode:: pycon >>> t = partial(translate, {'.': '_'}) >>> t('foo.bar') 'foo_bar' Examples: >>> translate('foo.bar@baz', {'.': '_', '@': '.'}) 'foo_bar.baz' """ def on_reduce(acc: str, kv: Tuple[str, str]) -> str: return acc.replace(kv[0], kv[1]) # table key/value return reduce(on_reduce, table.items(), s)