collections - How to easily convert IndexedSeq[Array[Int]] to Seq[Seq[Int]] in Scala? -

i have function takes list of lists of integer, seq[seq[int]]. produce data reading text file , using split, , produces list of array. not recognized scala, raises match error. either indexedseq or array alone ok seq[int] function, apparently nested collection issue. how can convert implicitly indexedseq[array[int]] seq[seq[int]], or how else other using tolist demonstrated below? iterable[iterable[int]] seems fine, instance, can't use this.

scala> def g(x:seq[int]) = x.sum g: (x: seq[int])int  scala> g("1 2 3".split(" ").map(_.toint)) res6: int = 6  scala> def f(x:seq[seq[int]]) = x.map(_.sum).sum f: (x: seq[seq[int]])int  scala> f(list("1 2 3", "3 4 5").map(_.split(" ").map(_.toint))) <console>:9: error: type mismatch;  found   : list[array[int]]  required: seq[seq[int]]               f(list("1 2 3", "3 4 5").map(_.split(" ").map(_.toint)))                                           ^  scala> f(list("1 2 3", "3 4 5").map(_.split(" ").map(_.toint).tolist)) res8: int = 18 

the problem array not implement seqlike. normally, implicit conversions arrayops or wrappedarray defined in scala.predef allow use array seq. however, in case array 'hidden' implicit conversions generic argument. 1 solution hint compiler can apply implicit conversion generic argument this:

def f[c <% seq[int]](x:seq[c]) = x.map(_.sum).sum 

this similar paul's response above. problem view bounds deprecated in scala 2.11 , using deprecated language features not idea. luckily, view bounds can rewritten context bounds follows:

 def f[c](x:seq[c])(implicit conv: c => seq[int]) = x.map(_.sum).sum 

now, assumes there implicit conversion c seq[int], indeed present in predef.