Listish

listish.Listish is a list-behaviour wrapper for arbitrary sequences and iterables (including iterators).

It acts as a mutable data wrapper for arbitrary inputs. On top of non-indexable input it also adds indexability.

Any iterable (including iterators) is supported:

>>> g = (x*7-1 for x in [6,2,1,7,9,33])
>>> l = Listish(g)
>>> l[3]
48

Complex slicing is supported:

>>> l = Listish(x for x in range(100) if x % 3)
>>> l[0:20:2]
[1, 4, 7, 10, 13, 16, 19, 22, 25, 28]

The input is used somewhat efficiently, only scanning far enough to retrieve the requested index:

>>> r = (x for x in range(10))
>>> l = Listish(r)
>>> l[4]
4
>>> next(r)
5
>>> print(warning)
In practise interfering with an iterable after passing it to this library is a bad idea, as we can see
>>> l[5]
6

Tupleish

listish.Tupleish provides indexing & persistence while presenting an immutable interface. listish.Listish inherits most of its functionality from listish.Tupleish, which is provided as a separate class for some kind of completeness.

See Also

itertools.tee, in the standard library, provides n iterables which proxy the same input iterable, while using the minimum required memory, which may be more suitable for some use cases than Listish or Tupleish, though it does not attempt to add enumerability or mutability.