fp.collections — Utilities for collections

New in version 0.1.

The fp.collections module provides utilities for working with collections.

fp.collections.get(monad_cls, key, collection)

A partial friendly version of lookup

>>> from fp.monads.maybe import Maybe
>>> get(Maybe, 'foo', {'foo': 'bar'})
Just('bar')

>>> get(Maybe, 'foo', {})
Nothing

fp.collections.get_nested(monad_cls, collection, *keys)

Get a value deep inside a nested data structure

>>> from fp.monads.maybe import Maybe
>>> data = {'foo': {'bar': {'baz': 'bing'}}}
>>> get_nested(Maybe, data, 'foo', 'bar', 'baz')
Just('bing')
>>> get_nested(Maybe, data, 'foo', 'bing')
Nothing
>>> get_nested(Maybe, data, 'blegh', 'bar')
Nothing
>>> get_nested(Maybe, {'foo': [{'bar': 'baz'}]}, 'foo', 0, 'bar')
Just('baz')
>>> get_nested(Maybe, {'foo': [{'bar': 'baz'}]}, 'foo', 1, 'bar')
Nothing
>>> get_nested(Maybe, {})
Just({})

fp.collections.lookup(monad_cls, collection, key)

Lookup a value by a key

>>> from fp.monads.maybe import Maybe
>>> lookup(Maybe, {'foo': 'bar'}, 'foo')
Just('bar')
>>> lookup(Maybe, {}, 'foo')
Nothing
>>> lookup(Maybe, [1, 2, 3], 2)
Just(3)
>>> lookup(Maybe, [1, 2, 3], 4)
Nothing
>>> lookup(Maybe, [1, 2, 3], 'not a int')
Nothing

>>> from fp.monads.either import Either
>>> lookup(Either, [1, 2, 3], 2)
Right(3)
>>> lookup(Either, [1, 2, 3], 4)
Left(IndexError('list index out of range',))