Expression returning List instead of Array

Question

When I do str.split("\|") by default it returns Array[string]. How do i get return type as List[String] instead of Array[string]. I was able to convert to List using toList. But, I was wondering is it possible to get it without toList.

scala> val str = "a|b|c"
str: String = a|b|c

scala> val arr = str.split("\\|")
arr: Array[String] = Array(a, b, c)

scala> val convList = arr.toList
convList: List[String] = List(a, b, c)

scala> val lis: List[String] = str.split("\\|")
<console>:11: error: type mismatch;
found   : Array[String]
required: List[String]
val lis: List[String] = str.split("\\|")

what is the problem with toList? Remember, String is the java.lang.String and its split returns an array. — Nabil A.
– Nabil A., Commented Sep 28, 2015 at 7:47
Thanks for response. Actually there were lot of array in full program but every where i wanted it to be List. Implicit conversion seems helpful — WoodChopper
– WoodChopper, Commented Sep 28, 2015 at 8:18
But implicit conversion is just syntactic sugar. It is still an array and you still call toList :) — Nabil A.
– Nabil A., Commented Sep 28, 2015 at 10:28

Fatih Donmez · Accepted Answer · 2015-09-28 08:07:17Z

1

You can implement an implicit conversion, then assignment will work without type error;

implicit def arrayToList[A](arr: Array[A]) = arr.toList

answered Sep 28, 2015 at 8:07

Fatih Donmez

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2 Comments

Travis Brown Over a year ago

Please don't do this. Implicit conversions are a bad idea in most cases (they now require a feature flag), and this conversion specifically is likely to make it much harder to reason about performance in your program. Just use toList, possibly via a helper method wrapping split.

Fatih Donmez Over a year ago

Thank you for bringing out, can you give a detailed link for further readings? @TravisBrown

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