scala - Converting mutable collection to immutable - Stack Overflow

scala - Converting mutable collection to immutable - Stack Overflow

If you want to convert ListBuffer into a List, use .toList. I mention this because that particular conversion is performed in constant time. Note, though, that any further use of the ListBuffer will result in its contents being copied first.

Otherwise, you can do collection.immutable.Seq(xs: _*), assuming xs is mutable, as you are unlikely to get better performance any other way.

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