Just because I can't resist writing little math things in Haskell: primes = 2 : ... | Hacker News

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piinbinary on July 11, 2019 | parent | context | favorite | on: Infinite work is less work

Just because I can't resist writing little math things in Haskell:

    primes = 2 : filter isPrime [3..]

    isPrime n =
      let divisors = takeWhile (\d -> d * d <= n) primes
      in not $ any (\d -> n `mod` d == 0) divisors

    strongPrimes =
      let primeTriples = zip3 primes (drop 1 primes) (drop 2 primes)
      in [b | (a, b, c) <- primeTriples, b*2 > a + c]

kdmccormick on July 11, 2019 | [–]

Proof that you can write something elegant in Haskell and use comprehensible variable names.

moomin on July 12, 2019 | [–]

I like the zip3, I should have thought of that. I think I prefer the mapMaybe, but then I avoid list comprehensions.

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