lz 0.10.2

"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 dependencies:

• with CPython

  python -m pip install -r requirements.txt
  

• with PyPy

  pypy -m pip install -r requirements.txt
  

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 release

Bump version

bump2version --verbose release

This will set version to major.minor.patch.

Running tests

Install dependencies:

• with CPython

  python -m pip install -r requirements-tests.txt
  

• with PyPy

  pypy -m pip install -r requirements-tests.txt
  

Plain

pytest

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