Viewing file:  _loop.py (1.21 KB) -rw-r--r--
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from typing import Iterable, Tuple, TypeVar
T = TypeVar("T")
def loop_first(values: Iterable[T]) -> Iterable[Tuple[bool, T]]:
"""Iterate and generate a tuple with a flag for first value."""
iter_values = iter(values)
try:
value = next(iter_values)
except StopIteration:
return
yield True, value
for value in iter_values:
yield False, value
def loop_last(values: Iterable[T]) -> Iterable[Tuple[bool, T]]:
"""Iterate and generate a tuple with a flag for last value."""
iter_values = iter(values)
try:
previous_value = next(iter_values)
except StopIteration:
return
for value in iter_values:
yield False, previous_value
previous_value = value
yield True, previous_value
def loop_first_last(values: Iterable[T]) -> Iterable[Tuple[bool, bool, T]]:
"""Iterate and generate a tuple with a flag for first and last value."""
iter_values = iter(values)
try:
previous_value = next(iter_values)
except StopIteration:
return
first = True
for value in iter_values:
yield first, False, previous_value
first = False
previous_value = value
yield first, True, previous_value
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