Flatten a list: Difference between revisions

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from itertools import (chain)

# ----------------------- FLATTEN ------------------------

# flatten :: NestedList a -> [a]

def flatten(x):

'''A list of atomic values resulting from fully ~~flattening~~

'''A list of atomic values resulting from fully

an arbitrarily nested list.~~'''~~

flattening an arbitrarily nested list.

'''

return concatMap(flatten)(x) if isinstance(x, list) else [x]

# ------------------------- TEST -------------------------

def main():

'''Test: flatten an arbitrarily nested list.~~'''~~

'''Test: flatten an arbitrarily nested list.

'''

print(

fTable(__doc__ + ':')(showList)(showList)(

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# ~~GENERIC~~ -------------------------------------------------

# ----------------------- GENERIC ------------------------

# compose (<<<) :: (b -> c) -> (a -> b) -> a -> c

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The list monad can be derived by using a function f which

wraps its output in a list,

(using an empty list to represent computational failure).~~'''~~

(using an empty list to represent computational failure).

'''

return ~~lambda xs: list(~~

~~chain.from_iterable~~(~~map(f,~~ xs))

def go(xs):

return chain.from_iterable(map(f, xs))

)

return go

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[[1],[[2]],[[[3, 4]]]] -> [1,2,3,4]

[[1],2,[[3, 4], 5],[[[]]],[[[6]]],7,8,[]] -> [1,2,3,4,5,6,7,8]</pre>

===Functional Non-recursive===