WithPartial

Introduction

WithPartial is a simple utility for functional piping in Python. The package exposes a context manager (used with with) called PipeContext, that allows you to access any function in any scope as a partial, meaning that it's naturally pipeable. Here's a contrived example from the test suite:

import numpy as np
from with_partial import PartialContext
from pipetools import pipe

with PartialContext() as _:
    ret = (
            10 > pipe |
            _.np.ones() |
            _.np.reshape(newshape=(5, 2)) |
            _.np.mean() |
            _.int()
    )
    assert ret == 1

As you can see, we were able to call both numpy and built-in functions on the _ object, and it executed the pipeline similarly to say R's magrittr package.

Installation

pip install with_partial

Usage

Actually WithPartial doesn't provide an actual piping mechanism, but it does add a useful syntax for use with pipes. For the actual piping mechanism, I suggest that you try pipetools, which this package is actually tested against.

WithPartial provides a single class: PipeContext. The way you use PipeContext is by first using it as a context manager:

with PipeContext() as _:

Then, using the return value of the context manager, which we have named _ (but you could call it anything), you access attributes and items (using .attr or ["key"] or [0]) to locate the function you want and then you finally call it (), which will create the partial. You can use positional and keyword arguments at this point if you need

For more usage information, refer to the test suite.

Tests

Note: you will need poetry installed.

git clone https://github.com/multimeric/WithPartial.git
cd WithPartial
poetry install --extras pipetools
poetry run pytest test/