CODEWITHSUNDEEP
scala
Barry
Barry

Reputation: 1820

Stream iterate can someone provide a walkthrough of this example code

So for splitting a number into its digits I found this code

    def split(n: Int) = if (n == 0) List(0) else { 
    (Stream.iterate(n)(_/10)takeWhile(_!=0)map(_%10)toList) reverse
}

code

which works but I couldn't explain to myself how the computation flows . Could anyone provide more insight into the intermediate steps it takes to go from

split(123) 
List[Int] = List(3,2,1)

It seems fairly straightforward but reading the method declarations and trying to work examples with calculator I failed to re-create myself the result.

Upvotes: 2

Views: 2072

Answers (1)

vvg
vvg

Reputation: 6385

Let's separate it into a stages:

(Stream.iterate(n)(_/10) // n - is first number, _/10 is function that recursively applied on given number
takeWhile(_!=0) // while result is not equal to 0
map(_%10) // got a list of numbers and take it by mod 10
toList)  // transform to list
reverse // take it in reverse order

scala> (Stream.iterate(123)(_/10)).takeWhile(_!=0).toList
res6: List[Int] = List(123, 12, 1)

Upvotes: 3

Related Questions