fcollections - functional collections for python

Motivation behind this library is to write long chain of map/filter sequence transformations without pain. To achieve that this library provides wrappers around standard python collections with additional methods defined.

Currently two wrappers are implemented -- Iterable and List.

Iterable

Iterable wraps any iterable entity and provides methods to work with it.

Of course, .filter(), .map() and .reduce() methods are provided:

>>> Iterable([4, 3, -1, 2, 1]).filter(lambda x: x > 0).map(str).reduce(str.__add__)
'4321'

.count method counts objects :) Argumentless .count() returns collections.Counter:

>>> Iterable([1, 1, 1, 5, 5, 3]).count()
Counter({1: 3, 5: 2, 3: 1})

and .count(object) method returns number of occurences for this specific value:

>>> Iterable([1, 1, 1, 5, 5, 3]).count(5)
2

Also there are many methods inspired by itertools module:

>>> Iterable([4, 3, -1, 2, 1]).groupby(lambda x: x % 2)
{0: [4, 2], 1: [3, -1, 1]}

>>> Iterable([4, 3, -1, 2, 1]).drop(1).take(2).list()
[-1, 2]

>>> Iterable([4, 3, -1, 2, 1]).dropuntil(lambda x: x < 0).list()
[-1, 2, 1]

>>> Iterable([4, 3, 4, 1, 1, 4]).unique().list()
[4, 3, 1]

There are also some methods which compute scalar value: min, max, len, all, any.

List

List wraps, well, standard python list. Obviously, List is also an Iterable and has all methods Iterable does. All operators are wrapped to, so adding List to a standard list results in a List.

Some methods like sort, returning None for standard list, return self for List resulting in more chaining possible:

>>> List([3, 2, 1]).append(-1).sort().map(lambda x: x**3).list()
 [-1, 1, 8, 27]

Plans for future

• Wrappers for the rest of standard python collections (dict, set, Counter).
• DictOfLists class to do cool things with result of .groupby().
• .plot() methods (inspired by .plot() method from pandas)

Any ideas are appreciated!