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Challenges Find n Niven Numbers

Scala, 52 bytes Stream.from(1).filter(x=>x%(x+"":\0)(_+_-48)<1).take Try it in Scastie! Woo, 3 deprecation warnings! (okay, one of them could be fixed but I like to live dangerously) St...

posted 2y ago by user‭  ·  edited 2y ago by user‭

Answer
#2: Post edited by user avatar user‭ · 2022-08-12T13:19:42Z (about 2 years ago)
  • # Scala, 52 bytes
  • ```scala
  • Stream.from(1).filter(x=>x%(x+"":\0)(_+_-48)<1).take
  • ```
  • [Try it in Scastie!](https://scastie.scala-lang.org/oMucQkxdSB23HjP0mYI8Pg)
  • Woo, 3 deprecation warnings! (okay, one of them could be fixed but I like to live dangerously)
  • # Scala, 52 bytes
  • ```scala
  • Stream.from(1).filter(x=>x%(x+"":\0)(_+_-48)<1).take
  • ```
  • [Try it in Scastie!](https://scastie.scala-lang.org/oMucQkxdSB23HjP0mYI8Pg)
  • Woo, 3 deprecation warnings! (okay, one of them could be fixed but I like to live dangerously)
  • `Stream.from(1)` constructs an infinite list of positive integers. Then we `filter` the `x`'s that are Niven numbers. `(x+"":\0)(_+_-48)` finds the sum of the `x`'s digits. A clearer way to write that would be `x.toString.foldRight(0)((sum, char) => sum + char.toInt - '0'.toInt)`. At the end, only the first `n` Niven numbers are `take`n from the infinite list.
#1: Initial revision by user avatar user‭ · 2022-08-12T13:16:09Z (about 2 years ago)
# Scala, 52 bytes

```scala
Stream.from(1).filter(x=>x%(x+"":\0)(_+_-48)<1).take
```

[Try it in Scastie!](https://scastie.scala-lang.org/oMucQkxdSB23HjP0mYI8Pg)

Woo, 3 deprecation warnings! (okay, one of them could be fixed but I like to live dangerously)