Catalan numbers/Pascal's triangle: Difference between revisions
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m (→Composition of pure functions: Preamble edit) |
(→Python :: Composition of pure functions: docstring edit) |
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derived from Pascal's triangle.''' |
derived from Pascal's triangle.''' |
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# diff :: [Int] -> Int |
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def diff(xs): |
def diff(xs): |
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'''Difference between the first two items in the list, |
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if its length is more than one. |
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Otherwise, the first (only) item in the list.''' |
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return ( |
return ( |
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xs[0] - (xs[1] if 1 < len(xs) else 0) |
xs[0] - (xs[1] if 1 < len(xs) else 0) |
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