Given the following Scala List:
val l = List(List("a1", "b1", "c1"), List("a2", "b2", "c2"), List("a3", "b3", "c3"))
How can I get:
List(("a1", "a2", "a3"), ("b1", "b2", "b3"), ("c1", "c2", "c3"))
Since zip can only be used to combine two Lists, I think you would need to iterate/reduce the main List somehow. Not surprisingly, the following doesn't work:
scala> l reduceLeft ((a, b) => a zip b) <console>:6: error: type mismatch; found : List[(String, String)] required: List[String] l reduceLeft ((a, b) => a zip b)
Any suggestions one how to do this? I think I'm missing a very simple way to do it.
Update: I'm looking for a solution that can take a List of N Lists with M elements each and create a List of M TupleNs.
Update 2: As it turns out it is better for my specific use-case to have a list of lists, rather than a list of tuples, so I am accepting pumpkin's response. It is also the simplest, as it uses a native method.
zip() method is a member of IterableLike trait, it is used to merge a collection to current collection and result is a collection of pair of tuple elements from both collections.
In Scala Stack class , the diff() method is used to find the difference between the two stacks. It deletes elements that are present in one stack from the other one. Return Type: It returns a new stack which consists of elements after the difference between the two stacks.
Specific to Scala, a list is a collection which contains immutable data, which means that once the list is created, then it can not be altered. In Scala, the list represents a linked list. In a Scala list, each element need not be of the same data type.
scala> (List(1,2,3),List(4,5,6),List(7,8,9)).zipped.toList res0: List[(Int, Int, Int)] = List((1,4,7), (2,5,8), (3,6,9))
For future reference.
I don't believe it's possible to generate a list of tuples of arbitrary size, but the transpose function does exactly what you need if you don't mind getting a list of lists instead.
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