All Questions
1,240
questions
0
votes
1
answer
48
views
How to apply pattern match when needed to match a middle element of a Seq() in scala
This is kind of a learning question rather than a programming code, I have a Sequence as below,
val inputSeq = Seq("A","B","C","D","E")
so I want to ...
- 51
0
votes
0
answers
61
views
List[Future[A]] => Future[(List[A], List[Throwable])] the most correct solution
I have solution:
def foo[A](futures: List[Future[A]])(implicit ec: ExecutionContext): Future[(List[A], List[Throwable])] =
futures.foldLeft(Future.successful(List.empty[A] -> List.empty[Throwable]...
- 1,664
-1
votes
1
answer
68
views
FoldLeft/FoldRight: Scala Compile-Errors
Trying to finish up an assignment and running into the following compiler errors:
fp2.scala:144: error: not enough arguments for method foldRight: (xs: List[A], e: B, f: (A, B) => B)B.
Unspecified ...
1
vote
2
answers
150
views
How to access List element present inside a map in scala?
I'm trying to learn scala from last couple of days so please bear with me.
I'm bit confused accessing the list element in scala. If it is accessed directly from a list apply method works however if it ...
- 45
0
votes
0
answers
43
views
Passing case class name as a function argument but takes entire path of case class
I have a case class
case class S3FileRecords(
rank: Integer,
name: String,
)
and while passing this case class name ...
1
vote
1
answer
70
views
Store a particular column values of a dataframe in comma separated format in a file in hdfs in scala
I have dataframe which has only one column containing json data strings in it.The size of this dataframe is 50M.I want to store this json strings in comma separated array format in specified numbers ...
- 29
1
vote
1
answer
26
views
replacing efficiently an element of a list in the same index with other a sub elements Scala [duplicate]
I want to add other elements to a list in the index of a given item.
for instance
val list = List(1,2,3,4)
I want to replace the element 3 with (3, 7) which will gives this output
val list = List(1,2,...
- 383
0
votes
1
answer
76
views
Tail Recursion in Scala return List Head each time after dropping it
I have a list of users. Each user might have a field users (like friends).
For each user I want to get the users related to that user and return each time the name.
Like some recursive function.
case ...
- 383
0
votes
2
answers
117
views
How to sort a list of custom objects by a specific field in Scala
I'm working on a Scala project where I need to sort a list of custom objects based on a specific field. The objects have a field called score, which is an integer. I want to sort the list of objects ...
- 524
1
vote
1
answer
65
views
How to add a element into another list at a certain index without removing or replacing any elements scala
I have a List and Map as below,
val exampleList = List("A","B","C","D","E","A","L","M","N")
val exampleMap =...
- 51
0
votes
3
answers
104
views
Scala: Sorting a list while keeping the position of placeholders
The problem I'm facing is sorting a List of Double values in Scala also containing some kind of placeholder values (Double.NaN in the example below. However, these can be set as required for the ...
- 25
0
votes
0
answers
131
views
How to get input to list from user in Scala?
Counting Change
Write a recursive function that counts how many different ways you can make change for an amount, given a list of coin denominations. For example, there are 3 ways to give change for 4 ...
2
votes
2
answers
333
views
Could not infer type of parameter
I have created MyList abstract class to implement the list, the reason for not using already present list implementation is I am learning Scala and this was exercise for the same course. I am writing ...
0
votes
1
answer
441
views
Scala: add prefix to each element in list
I have a list of some partitions, like:
[1, 2, 3, 4]
and also I have main path, like:
"books/style/type="
I want to get a list of full path, like this:
[books/style/type=1/, books/style/...
- 37
1
vote
1
answer
76
views
I have a List[(List[A], List[R])] - a List of a tuple of two Lists of objects A and R respectively. How do I "flatten" the List[R] for each List[A]?
I have a List[(List[A], List[R])] - a List of a tuple of two Lists of objects A and R respectively.
For example, List[([A1, A2], [R1, R2, R3])]
What I want to do is convert this into a List[(List[A], ...
- 35