CODEWITHSUNDEEP
scala
Andy Smith
Andy Smith

Reputation: 151

Scala List of tuples to flat list

I have list of tuple pairs, List[(String,String)] and want to flatten it to a list of strings, List[String].

Upvotes: 12

Views: 12662

Answers (5)

Michael T
Michael T

Reputation: 1043

See -

https://stackoverflow.com/a/43716004/4610065

In this case -

import syntax.std.tuple._
List(("John","Paul"),("George","Ringo")).flatMap(_.toList)

Upvotes: 0

elm
elm

Reputation: 20415

In general for lists of tuples of any arity, consider this,

myTuplesList.map(_.productIterator.map(_.toString)).flatten

Note the productIterator casts all types in a tuple to Any, hence we recast values here to String.

Upvotes: 3

Keith Pinson
Keith Pinson

Reputation: 1725

Try:

val tt = List(("John","Paul"),("George","Ringo"))
tt.flatMap{ case (a,b) => List(a,b) }

This results in:

List(John, Paul, George, Ringo)

Upvotes: 6

ale64bit
ale64bit

Reputation: 6242

Well, you can always use flatMap as in:

list flatMap (x => List(x._1, x._2))

Although your question is a little vague.

Upvotes: 10

Gábor Bakos
Gábor Bakos

Reputation: 9100

Some of the options might be: concatenate:

list.map(t => t._1 + t._2)

one after the other interleaved (after your comment it seems you were asking for this):

list.flatMap(t => List(t._1, t._2))

split and append them:

list.map(_._1) ++ list.map(_._2)

Upvotes: 21

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