What I am trying to do is keep an original list and two duplicated ones in which to perform operations. Say orginalList is a list of String and has 5 entries
duplicatedList = originalList
secondDuplicatedList = orignalList
duplicatedList.remove(0)
secondDuplicatedList.remove(1)
The values are removed from all three lists and at the end all three lists will have 3 entries.
I have seen a lot of similar questions, but I do not quite get it
Any help or suggestion would be great. thanks
duplicatedList = originalList
Using equal sign will make another pointer to the same location in memory (duplicatedList is not instantiated from scratch); so both duplicatedList & originalList points to the same list
Instead, you need to create a brand new list in memory with the same values of the original list.
You can use the Collection's extension function toMutableList() to do that:
duplicatedList = originalList.toMutableList()
secondDuplicatedList = originalList.toMutableList()
This extension function originally creates a new list:
public fun <T> Collection<T>.toMutableList(): MutableList<T> {
return ArrayList(this)
}