"""General shared utilities."""
import logging
import re
from itertools import tee, zip_longest
from typing import Any, Iterable, Tuple
# Do not update the version manually - it is managed by `bumpversion`.
log = logging.getLogger(__name__)
#: Regular expression for stripping non-alphanumeric characters
NON_ALPHANUMERIC_STRIP_RE = re.compile(r'[\W_]+')
def is_blank(string: str) -> bool:
"""Return True iff the string contains only whitespaces."""
return not string.strip()
def pairwise(
iterable: Iterable,
default_value: Any,
) -> Iterable[Tuple[Any, Any]]:
"""Return pairs of items from `iterable`.
pairwise([1, 2, 3], default_value=None) -> (1, 2) (2, 3), (3, None)
"""
a, b = tee(iterable)
_ = next(b, default_value)
return zip_longest(a, b, fillvalue=default_value)
def common_prefix_length(a: str, b: str) -> int:
"""Return the length of the longest common prefix of a and b.
>>> common_prefix_length('abcd', 'abce')
3
"""
for common, (ca, cb) in enumerate(zip(a, b)):
if ca != cb:
return common
return min(len(a), len(b))
def strip_non_alphanumeric(string: str) -> str:
"""Strip string from any non-alphanumeric characters."""
return NON_ALPHANUMERIC_STRIP_RE.sub('', string)
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