Department numbers: Difference between revisions
→{{header|Python}}: Updated bind, pylinted for Python 3, added subheaders.
(Added Algol W) |
(→{{header|Python}}: Updated bind, pylinted for Python 3, added subheaders.) |
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=={{header|Python}}==
===Procedural===
<lang python>from itertools import permutations
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14: 6 5 1 </pre>
===Composition of pure functions===
{{Works with|Python|3}}
<lang python>'''Department numbers'''
from operator import (
# options :: Int -> Int -> Int -> [(Int, Int, Int)]
def options(lo, hi, total):
'''Eligible integer triples.'''
ds =
return bind(filter(lambda x: 0 == x % 2, ds))(▼
lambda x: bind(filter(curry(ne)(x), ds))(
lambda y: bind([total - (x + y)])(
lambda z: [(x, y, z)] if (
z != y and
) else []
)
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# TEST ----------------------------------------------------
# main :: IO ()
def main():
'''Test'''
xs = options(1, 7, 12)
print
for tpl in xs:
print
print
# GENERIC
# bind (>>=) :: [a] -> (a -> [b]) -> [b]
def bind(xs):
'''List monad injection operator.
return lambda f: reduce(add, map(f, xs), [])▼
Two computations sequentially composed,
with any value produced by the first
passed as an argument to the second.'''
return lambda f: list(
chain.from_iterable(
map(f, xs)
)
)
# curry :: ((a, b) -> c) -> a -> b -> c
main()</lang>▼
def curry(f):
'''A curried function derived
from an uncurried function.'''
# enumFromTo :: (Int, Int) -> [Int]
def enumFromTo(m):
'''Integer enumeration from m to n.'''
# even :: Int -> Bool
def even(x):
'''True if x is an integer
multiple of two.'''
return 0 == x % 2
if __name__ == '__main__':
▲ main()</lang>
{{Out}}
<pre>('Police', 'Sanitation', 'Fire')
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