lz 0.9.0

"Lazy" calculations support.

lz

In what follows

• python is an alias for python3.5 or any later version (python3.6 and so on),
• pypy is an alias for pypy3.5 or any later version (pypy3.6 and so on).

Installation

Install the latest pip & setuptools packages versions:

• with CPython

  python -m pip install --upgrade pip setuptools
  

• with PyPy

  pypy -m pip install --upgrade pip setuptools
  

User

Download and install the latest stable version from PyPI repository:

• with CPython

  python -m pip install --upgrade lz
  

• with PyPy

  pypy -m pip install --upgrade lz
  

Developer

Download the latest version from GitHub repository

git clone https://github.com/lycantropos/lz.git
cd lz

Install:

• with CPython

  python setup.py install
  

• with PyPy

  pypy setup.py install
  

Usage

lz provides a bunch of utilities for working with functions, predicates & iterables such as

1. function composition

   >>> from lz.functional import compose
   >>> sum_of_first_n_natural_numbers = compose(sum, range)
   >>> sum_of_first_n_natural_numbers(10)
   45
   

2. currying

   >>> from lz.functional import curry 
   >>> curried_power = curry(pow) 
   >>> two_to_power = curried_power(2) 
   >>> two_to_power(10)
   1024
   

3. flipping positional parameters order

   >>> from lz.functional import flip
   >>> flipped_power = flip(pow)
   >>> flipped_power(2, 4)
   16
   

4. packing function's arguments

   >>> from lz.functional import pack
   >>> packed_int = pack(int)
   >>> packed_int(['10'])
   10
   >>> packed_int(['10'], {'base': 2})
   2
   

5. left partial application

   >>> from lz import left
   >>> count_from_zero_to = left.applier(range, 0)
   >>> list(count_from_zero_to(10))
   [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
   

6. right partial application

   >>> from lz import right
   >>> square = right.applier(pow, 2)
   >>> square(10)
   100
   

7. negating predicate

   >>> from lz.logical import negate
   >>> false_like = negate(bool)
   >>> false_like([])
   True
   >>> false_like([0])
   False
   

8. conjoining predicates

   >>> from lz.logical import conjoin
   >>> is_valid_constant_identifier = conjoin(str.isupper, str.isidentifier)
   >>> is_valid_constant_identifier('SECOND_SECTION')
   True
   >>> is_valid_constant_identifier('2ND_SECTION')
   False
   

9. disjoining predicates

   >>> from lz.logical import disjoin
   >>> alphabetic_or_numeric = disjoin(str.isalpha, str.isnumeric)
   >>> alphabetic_or_numeric('Hello')
   True
   >>> alphabetic_or_numeric('42')
   True
   >>> alphabetic_or_numeric('Hello42')
   False
   

10. exclusive disjoining predicates

    >>> from lz.logical import exclusive_disjoin
    >>> from keyword import iskeyword
    >>> valid_object_name = exclusive_disjoin(str.isidentifier, iskeyword)
    >>> valid_object_name('valid_object_name')
    True
    >>> valid_object_name('_')
    True
    >>> valid_object_name('1')
    False
    >>> valid_object_name('lambda')
    False
    

11. reversing sequences and any string streams

    >>> from lz.reversal import reverse
    >>> list(reverse(range(10)))
    [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
    >>> import io
    >>> list(reverse(io.BytesIO(b'Hello\nWorld!')))
    [b'World!', b'Hello\n']
    

12. chunking iterable

    >>> from lz.iterating import chopper
    >>> to_triplets = chopper(3)
    >>> list(map(tuple, to_triplets(range(10))))
    [(0, 1, 2), (3, 4, 5), (6, 7, 8), (9,)]
    

13. sliding over iterable

    >>> from lz.iterating import slider
    >>> slide_pairwise = slider(2)
    >>> list(slide_pairwise(range(10)))
    [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 7), (7, 8), (8, 9)]
    

14. interleaving iterables

    >>> from lz.iterating import interleave
    >>> list(interleave([range(10), range(10, 20)]))
    [0, 10, 1, 11, 2, 12, 3, 13, 4, 14, 5, 15, 6, 16, 7, 17, 8, 18, 9, 19]
    

15. iterable transposition

    >>> from lz.transposition import transpose
    >>> list(map(tuple, transpose(zip(range(10), range(10, 20)))))
    [(0, 1, 2, 3, 4, 5, 6, 7, 8, 9), (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)]
    

16. iterable duplication

    >>> from lz.replication import duplicate
    >>> list(map(tuple, duplicate(range(10))))
    [(0, 1, 2, 3, 4, 5, 6, 7, 8, 9), (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)]
    

and many more.

Development

Building docs

Install project in editable mode

• with CPython

  python -m pip install -e .
  

• with PyPy

  pypy -m pip install -e .
  

Install docs requirements

• with CPython

  python -m pip install -r docs/requirements.txt
  

• with PyPy

  pypy -m pip install -r docs/requirements.txt
  

Build docs

cd docs
make html

Bumping version

Preparation

Install bump2version.

Pre-release

Choose which version number category to bump following semver specification.

Test bumping version

bump2version --dry-run --verbose $CATEGORY

where $CATEGORY is the target version number category name, possible values are patch/minor/major.

Bump version

bump2version --verbose $CATEGORY

This will set version to major.minor.patch-alpha.

Release

Test bumping version

bump2version --dry-run --verbose --tag release

Bump version

bump2version --verbose --tag release

This will set version to major.minor.patch and add Git tag.

Notes

To avoid inconsistency between branches and pull requests, bumping version should be merged into master branch as separate pull request.

Running tests

Plain:

• with CPython

  python setup.py test
  

• with PyPy

  pypy setup.py test
  

Inside Docker container:

• with CPython

  docker-compose --file docker-compose.cpython.yml up
  

• with PyPy

  docker-compose --file docker-compose.pypy.yml up
  

Bash script (e.g. can be used in Git hooks):

• with CPython

  ./run-tests.sh
  

  or

  ./run-tests.sh cpython
  

• with PyPy

  ./run-tests.sh pypy
  

PowerShell script (e.g. can be used in Git hooks):

• with CPython

  .\run-tests.ps1
  

  or

  .\run-tests.ps1 cpython
  

• with PyPy

  .\run-tests.ps1 pypy