Scalacheck generate Gen.alphastr with the same length

Question

I need to generate strings with the same length. I can't realize how. Many thanks

val s = for {
  x <- Gen.alphaStr
} yield ...

score 20 · Accepted Answer · edited Jun 12 '20 at 08:37

20

example code:

import org.scalacheck.Gen
import org.scalacheck.Prop.forAll    

// strGen generates a fixed length random string
val strGen = (n: Int) => Gen.listOfN(n, Gen.alphaChar).map(_.mkString)

val fixedLengthStr = forAll(strGen(10)){ s =>
  s.length == 10
}

fixedLengthStr.check

to inspect a generated string use:

strGen(5).sample

edited Jun 12 '20 at 08:37

Stephen Thompson

29
1
6

answered Nov 10 '14 at 15:44

j-keck

1,021
1
7
13

score -2 · Answer 2 · edited Jun 14 '20 at 17:00

-2

There is a suchThat(f: T => Boolean): Gen[T] = new Gen[T] on Gen, so could be used like

val stringShorterThan = (n: Int) => Gen.alphaStr.suchThat(s => s.length <= n)
val string64 = stringShorterThan(64)

edited Jun 14 '20 at 17:00

Stephen Thompson

29
1
6

answered Nov 11 '18 at 10:15

Дмитрий Завориин

27
1

1

Such a generator would discard many values because of the use of `suchThat` – Valy Dia Feb 16 '19 at 12:18
1

You'd be better off just truncating the string `Gen.alphaStr..map(str => if (str.length <= max) str else str.substring(0,max))` – Travis Stevens May 13 '19 at 08:29

Scalacheck generate Gen.alphastr with the same length

2 Answers2

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