How to remove duplicate values from list using scala?

Question

I have following list

List(List
(43673,38448,512,36398,1500,**BpEwv+EcDv3z**,58f39535-03b7-4e05-a2d8-3f5b424c8938),
List(302750,759,512,759,3796,**BpEwv+EcDv3v**,069865df-30c3-48c3-bf02-79f2fcff7213),
List(616278,1600,512,107418,15255,**BpEwv+EcDv3v**,b373b731-6f38-4559-808e-1c05fc06af00),
List(0,0,512,0,0,**BpEwv+EcDv3z**,24894b9f-9e30-4073-a538-186a312c670e)
)

I want to remove duplicate values marked in bold (6th index of list for all elements) from this list. The sequence of elements is fixed.

Expected output:

List(
List(43673,38448,512,36398,1500,BpEwv+EcDv3z,58f39535-03b7-4e05-a2d8-3f5b424c8938),
List(302750,759,512,759,3796,BpEwv+EcDv3v,069865df-30c3-48c3-bf02-79f2fcff7213))

How do I remove duplicate values from list using scala??

I want it to work slighlty different. Here I want to remove duplicates only on fields marked as ** and in blue color and also its a list of list — user3322141
– user3322141, Commented Nov 6, 2014 at 4:44
You want to remove duplicates or you want to remove all occurrences of a specific value? — Nader Ghanbari
– Nader Ghanbari, Commented Nov 6, 2014 at 5:03
Can you see my edit please??? I have list of list and want list by remove whole inner list if any specific value gets duplicated.. — user3322141
– user3322141, Commented Nov 6, 2014 at 5:20
Just a suggestion, it will be useful to give values like A, B instead of BpEwv+EcDv3z and BpEwv+EcDv3v which is different by only one character. It took quite a long time to understand what you want even after the expected solution that you posted. — mohit
– mohit, Commented Nov 6, 2014 at 6:11

Nader Ghanbari · Accepted Answer · 2014-11-06 05:09:08Z

2

If you want to remove all occurrences of a specific value in all Lists you can use the following code:

val lss = List(List(1,2,2), List(1,2,3,4,2))

lss map (_.filter(_ != 2))           //  List(List(1), List(1, 3, 4))

which removes all occurrences of 2 in all Lists.

If you want to get a single List in return you can use flatMap:

lss flatMap (_.filter(_ != 2))        // List(1, 1, 3, 4)

answered Nov 6, 2014 at 5:09

Nader Ghanbari

4,3501 gold badge27 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

mohit · Accepted Answer · 2014-11-06 06:20:52Z

Based on your expected output, you can do something like

scala> val a = List(List
 | (43673,38448,512,36398,1500,"BpEwv+EcDv3z","58f39535-03b7-4e05-a2d8-3f5b424c8938"),
 | List(302750,759,512,759,3796,"BpEwv+EcDv3v","069865df-30c3-48c3-bf02-79f2fcff7213"),
 | List(616278,1600,512,107418,15255,"BpEwv+EcDv3v","b373b731-6f38-4559-808e-1c05fc06af00"),
 | List(0,0,512,0,0,"BpEwv+EcDv3z","24894b9f-9e30-4073-a538-186a312c670e")
 | )
a: List[List[Any]] = List(List(43673, 38448, 512, 36398, 1500, BpEwv+EcDv3z, 58f39535-03b7-4e05-a2d8-3f5b424c8938), List(302750, 759, 512, 759, 3796, BpEwv+EcDv3v, 069865df-30c3-48c3-bf02-79f2fcff7213), List(616278, 1600, 512, 107418, 15255, BpEwv+EcDv3v, b373b731-6f38-4559-808e-1c05fc06af00), List(0, 0, 512, 0, 0, BpEwv+EcDv3z, 24894b9f-9e30-4073-a538-186a312c670e))

scala> a.groupBy(_(5)).mapValues(_(0)).map(_._2)
res0: scala.collection.immutable.Iterable[List[Any]] = List(List(302750, 759, 51
2, 759, 3796, BpEwv+EcDv3v, 069865df-30c3-48c3-bf02-79f2fcff7213), List(43673, 3
8448, 512, 36398, 1500, BpEwv+EcDv3z, 58f39535-03b7-4e05-a2d8-3f5b424c8938))

You can also do which reads a little better

scala> a.groupBy(_(5)).mapValues(_(0)).values.toList
res6: List[List[Any]] = List(List(302750, 759, 512, 759, 3796, BpEwv+EcDv3v, 069865df-30c3-48c3-bf02-79f2fcff7213), List(43673, 38448, 512, 36398, 1500, BpEwv+EcDv3z, 58f39535-03b7-4e05-a2d83f5b424c8938))

Collectives™ on Stack Overflow

How to remove duplicate values from list using scala?

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related