prevcurrnext 0.1.1

Iteration utils for "prev", "curr", and "next"-style for-loops.

prevcurrnext

Iteration utils for "prev", "curr", and "next"-style for-loops.

Install

pip install prevcurrnext

Usage

The prevcurrnext function yields pairs of consecutive elements from an iterable, allowing you to see the "previous", "current", and "next" items for each element. It includes options to yield None at the beginning and/or end of the sequence for convenient boundary handling.

from prevcurrnext import prevcurr, currnext, prevcurrnext

# Basic usage
for prev, curr in prevcurr([1, 2, 3]):
    print(prev, curr)
# Output:
# None 1
# 1 2
# 2 3

# Customizing boundary behavior
# Adding None at the end
for prev, curr in prevcurr([1, 2, 3], end_curr_on_none=True):
    print(prev, curr)
# Output:
# None 1
# 1 2
# 2 3
# 3 None

for curr, _next in currnext([1, 2, 3]):
    print(curr, _next)
# Output:
# 1 2
# 2 3
# 3 None

for prev, curr, _next in prevcurrnext([1, 2, 3]):
    print(prev, curr, _next)
# Output:
# None 1 2
# 1 2 3
# 2 3 None

Available functions

• currprev
• prevcurr
• currnext
• nextcurr
• prevcurrnext
• nextcurrprev

All functions have nearly the exact same parameters:

• iterable: The iterable to process.
• start_prev_on_none: Whether to yield None for the "previous" item before the first element. Default is True.
• end_curr_on_none: Whether to yield None for the "current" item after the last element. Default is False.
• end_next_on_none: Whether to yield None for the "next" item after the last element. Default is True.

Contributing

Contributions are welcome! If you find issues or have suggestions, please open an issue or submit a pull request on GitHub.

Development Setup

If you use Poetry

poetry install
poetry run pytest

Otherwise...

python -m venv venv
source venv/bin/activate
pip install -r requirements-dev.txt
pip install -e .
pytest

License

This project is licensed under the MIT License.