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)