witertools.

witertools provides:

• functions that take a function that returns and iterator, and return a function that returns list.
• wrappers around built in functions that return iterators (filter, map, and zip)
• wrappers around the functions in itertools except count, cycle, and repeat
• wrappers around the functions in more_itertools

The motivation as that itertools and more-itertools in particular have functions that return iterators, but very frequently the desired result is a list. Over and over in code you will see repeated code of calling list on the result of a function that produces an interator. You will even see it in most examples in the more-itertools api.

Wrappers Around Functions that Return Iterators

In witertools: iterator_to_list_function will take a function that returns an iterable, and return a function that returns a list.

>>> from witertools import *
>>> f=iterator_to_list_function(filter)
>>> w.filter(lambda s: True, [3,4,5])     
[3, 4, 5]

iterator_name_to_list_function will take a module object and a function name, and return a function that returns a list.

>> g=iterator_name_to_list_function(__builtins__,"filter") 
>>> g(lambda s : True , [1,2]) 
[1, 2]

Wrappers Around Built in Functions

To use a wrapper around a built in function, just use a function from the same name from the witertools package.

>>> import witertools as w 
>>> w.filter(lambda s: True, [3,4,5])
[3, 4, 5]

which replaces

[3, 4, 5]

Wrappers Around itertools

Use a function from the witertools.itertools namespace, with the same name as the function in the itertools namespace.

>>> i.chain([1,3],[4,5])
[1, 3, 4, 5]

Wrappers Around more-itertools

Use a function from the witertools.more_itertools namespace, with the same name as the function in the more-itertools namespace. You will need to install more-itertools to use these functions, as more-itertools as not a prequisite of witertools.

>>> from witertools.more_itertools import chunked
>>> chunked([1, 2, 3, 4, 5, 6], 3)
[[1, 2, 3], [4, 5, 6]]

There are a few functions in more_itertools that do not return iterables. For example, nth_or_last. These functions are still wrapped in witertools.more_itertools but will result in a traceback.

>>> from witertools.more_itertools import  nth_or_last
>>> nth_or_last([0, 1, 2, 3], 2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Program Files (x86)\Python39-32\lib\site-packages\witertools\iterator_to_list.py", line 7, in as_list
    return list(iterator_function(*args,**kwargs))
TypeError: 'int' object is not iterable