namedzip 1.0.6

Extends zip() and itertools.zip_longest() to generate named tuples.

This Python package implements namedzip and namedzip_longest, which extend zip and itertools.zip_longest respectively to generate named tuples using collections.namedtuple.

Installation

$ pip install namedzip

Usage examples

>>> from namedzip import namedzip, namedzip_longest

namedzip and namedzip_longest can either be used with iterable positional arguments, like the interfaces which they extend, to return generator objects:

>>> iterables = (["A", "B", "C"], [1, 2, 3])
>>> pairs = namedzip(*iterables, typename="Pair", field_names=("letter", "number"))
>>> for pair in pairs:
...     print(pair)
...
Pair(letter='A', number=1)
Pair(letter='B', number=2)
Pair(letter='C', number=3)
>>>
>>> iterables = (["A", "B"], [1, 2, 3])
>>> pairs = namedzip_longest(*iterables, typename="Pair", field_names=("letter", "number"), defaults=("X", 99))
>>> for pair in pairs:
...     print(pair)
...
Pair(letter='A', number=1)
Pair(letter='B', number=2)
Pair(letter='X', number=3)
>>>

Or without positional arguments to return reusable function objects:

>>> zip_pairs = namedzip(typename="Pair", field_names=("letter", "number"))
>>> pairs = zip_pairs(["A", "B", "C"], [1, 2, 3])
>>> for pair in pairs:
...     print(pair)
...
Pair(letter='A', number=1)
Pair(letter='B', number=2)
Pair(letter='C', number=3)
>>>
>>> zip_pairs = namedzip_longest(typename="Pair", field_names=("letter", "number"), defaults=("X", 99))
>>> pairs = zip_pairs(["A", "B", "C"], [1, 2])
>>> for pair in pairs:
...     print(pair)
...
Pair(letter='A', number=1)
Pair(letter='B', number=2)
Pair(letter='C', number=99)
>>>

Purpose: Why / how could this be useful?

The main idea behind this package is to help improve readability in cases where you have a need to iterate over more than just a few collections/streams of data. Instead of messing with indices or unpacking long tuples, namedzip allows you to access aggregated values by attribute names.

A small hypothetical example of iterating over streams of sensor data in three ways:

zip_data = namedzip(
    typename="Data", field_names=("temp_f", "humidity", "wind_mph", "pressure_hpa")
)

# Accessing values by attribute names.
for data in zip_data(temperature_f, humidity, wind_mph, pressure_hpa):
    temp_c = (data.temp_f - 32) / 1.8
    wind_knots = data.wind_mph / 1.15078
    pressure_atm = data.pressure_hpa / 1013.25
    dew_point = calculate_dew_point(temp_c, data.humidity)

# Accessing values by indices.
for data in zip(temperature_f, humidity, wind_mph, pressure_hpa):
    temp_c = (data[0] - 32) / 1.8
    wind_knots = data[2] / 1.15078
    pressure_atm = data[3] / 1013.25
    dew_point = calculate_dew_point(temp_c, data[1])

# Unpacking values in for statement.
for temp_f, humidity, wind_mph, pressure_hpa in zip(temperature_f, humidity, wind_mph, pressure_hpa):
    temp_c = (temp_f - 32) / 1.8
    wind_knots = wind_mph / 1.15078
    pressure_atm = pressure_hpa / 1013.25
    dew_point = calculate_dew_point(temp_c, humidity)

# NOTE: The formulas included above have not been checked and may not be accurate.

Additionally, namedzip_longest allows for individual default values to be specified for each iterable which zip_longest does not.

Documentation

Additional documentation is available at https://namedzip.readthedocs.io/en/latest/.

Development setup

Clone repo:

$ git clone https://github.com/erberlin/namedzip.git
$ cd namedzip

Create and activate virtual environment on Windows:

> python -m venv venv
> venv\Scripts\activate

Create and activate virtual environment on OS X & Linux:

$ python3 -m venv venv
$ source venv/bin/activate

Install development packages:

$ pip install -r requirements.txt

Run test suite:

$ pytest -v

Meta

Erik R Berlin - [e-mail]

Distributed under the MIT license. See LICENSE for more information.

https://github.com/erberlin/namedzip