This is a companion discussion topic for the original entry at https://www.raywenderlich.com/7910496-programming-in-kotlin-fundamentals/lessons/16
This is a companion discussion topic for the original entry at https://www.raywenderlich.com/7910496-programming-in-kotlin-fundamentals/lessons/16
When I convert the array to list using this method:
val gamesList = mutableListOf(gamesArray)
The following both lines result in a build error
gamesList.addAll(listOf(“Poker”,“Pool”))
gamesList.remove(“Gymnastics”)
But if the array is made into a list using the following:
val gamesList = gamesArray.toMutableList()
The code compiles without error.
Why the difference when both methods create a MutableList type?
Hey @pallavis!
When you use the first approach:
val gamesList = mutableListOf(gamesArray)
You actually create a MutableList<Array>. Because of that, you can only add elements to the list that are arrays too. It doesn’t flatten them at all.
However, the second approach:
val gamesList = gamesArray.toMutableList()
You take the array and convert it into a mutable list. So you get a MutableList essentially. That way you can add elements from other lists or remove specific games.
Hope this makes sense! :]
Perfectly.
val gamesList = mutableListOf(gamesArray) creates a two-dimensional collection (though in my case it has one element only - the gamesArray).
Whereas val gamesList = gamesArray.toMutableList() creates a list out of the elements of gamesArray.
Thank you, Filip. 