Android Question How many values appear (in sequence) code snippet help?

[Mashiane]

Hi there

I need some list conversion code snippet. Assume my list contains these values...

2,2,2,5,6,2,1,3,5,7,9,10,10,6,6,4,4,4,4,2,2,2,2

I need a snippet that will return a map maintaining the sequencing of the values and how many times they appear. From above, the output should be

2-3,5-1,6-1,2-1,1-1,3-1,5-1,7-1,9-1,10-2,6-2,4-4,2-4

What the code snippet should do...

1. Pass the list of values in the list (whether sorted / unsorted)
2. The code snippet should detect per value, how many they are e.g 2,2,2 = 2-3, meaning the value 2 appears 3 times
3. The sequence of values should be maintained i.e. there can be another sequence for the same value somewhere in the list, e.g. we start with value 2 and end with value 2.

Thanks a lot!

 

[JordiCP]

As a map can not hold different entries for a same key, the snippet could return for instance another list of a custom type

Something like this (assumes the list is non-empty and populated with ints)

Sub Process_Globals
  Type sequencePair(value as int, numTimes as int)
End Sub
Sub Activity_Create(FirstTime as Boolean)
   '...
   Dim l As List
   l.Initialize
   l.AddAll(Array As Int(2,2,2,3,4,4,1,1,1,1,1,3,3,7,7,7,7,2,2,8,2))
   Dim l2 As List=FindSequences(l)
   For k=0 To l2.Size-1
     Dim pSeq As sequencePair = l2.Get(k)
     Log(pSeq.value&"-"&pSeq.numTimes)
   Next

Ens Sub

Sub FindSequences(srcList as List) as List
   Dim dstList as List
   dstList.initialize 
   Dim currentSequencePair as sequencePair
   currentSequencePair.initialize
   currentSequencePair.value=srcList.Get(0)
   currentSequencePair.numTimes=1
   For k=1 to srcList.size-1  '<-- edited!! (originally was 0)
      Dim newVal as int=srcList.Get(k)
      If newVal=currentSequencePair.value Then
         currentSequencePair.numTimes=currentSequencePair.numTimes+1
      Else
         dstList.Add(currentSequencePair)
         Dim currentSequencePair as sequencePair
         currentSequencePair.initialize
         currentSequencePair.value = newVal
         currentSequencePair.numTimes=1
     End If
   Next
   If currentSequencePair.numTimes>0 Then dstList.add(currentSequencePair)
   Return dstList
End Sub

 

[Mashiane]

Wow, that was quick. Thanks a million bud!

 

[sorex]

sorry, wrong interpretation

 

[JordiCP]

uhmmmm...yes but

3. The sequence of values should be maintained i.e. there can be another sequence for the same value somewhere in the list, e.g. we start with value 2 and end with value 2.

the request was not to count the totals but repeated sequences: 2-3,5-1,6-1,2-1,1-1,3-1,5-1,7-1,9-1,10-2,6-2,4-4,2-4

 

[sorex]

indeed, I saw it after I posted it. what he wants is actually an RLE lookup loop.