Android Question How do I save a list of maps to a CSV?

[Tim Chapman]

I load the following csv file:

"Skill Name","Total","Mod","Key","Ranks","Class","CC","Trained","SP","Misc","Synergy","TCP"
"Left","Center","Center","Center","Center","Center","Center","Center","Center","Center","Center","Center"
"Appraise",6,3,"Int",0,,true,false,0,3,0,0
"Balance",-1,2,"Dex",0,,true,false,0,0,0,-3
"Bluff",1,1,"Cha",0,,true,false,0,0,0,0
"Climb (with climb kit)",2,2,"Str",1,"F,A",false,false,1,2,0,-3

Then convert it to a list of maps with this code:

Sub LoadCSVFromFile(FileDir As String, FileName As String, ListOfMaps As List, HeaderList As List, Justification As Map)
    Dim ListFromFile As List
    Dim ReturnMap As Map : ReturnMap.Initialize()
    Dim cells() As String
    Dim su As StringUtils
  
    'Load Skill List from file
    ListFromFile.Initialize
    ListFromFile = su.LoadCSV2(FileDir, FileName, ",", HeaderList)
    Log("ListFromFile = " & ListFromFile)      
  
    'Populate Justification Map from 1st row in ListFromFile.  Note that the header row is not counted because the HeaderList took that from the count.
    Justification.Initialize()
    cells = ListFromFile.Get(0)
    For j = 0 To HeaderList.Size -1
        Justification.Put(HeaderList.Get(j), cells(j))
    Next

    'Populate List of Maps (one map for each skill, spell, etc.)
    For i = 1 To ListFromFile.Size - 1
        cells = ListFromFile.Get(i)
        Dim ItemMap As Map
        ItemMap.Initialize()
        For j = 0 To HeaderList.Size - 1
            ItemMap.Put(HeaderList.Get(j), cells(j))
        Next
        ListOfMaps.Add(ItemMap)
    Next
End Sub

I want to convert the list of maps back to the original csv file format and save it. I have been trying for hours to get that done with no success. How can I do this?
Thanks again for assistance!

 

[Erel]

1. No need to initialize ListFromFile as you are assigning it a different list anyway.

2. Convert the list of maps to a list of arrays:

Dim listOfArrays As List
listOfArrays.Initialize
For Each item As Map In ListOfMaps
 Dim row(HeaderList.Size) As String
 For c = 0 To HeaderList.Size - 1
  row(c) = item.Get(HeaderList.Get(c))
 Next
 listOfArrays.Add(row)
Next

 

[Tim Chapman]

Thanks Erel,
I am trying to save it back to a csv file like the original.
I tried to save a list of arrays to a csv file and can't do so. They can't be cast as string. I get a java exception to that effect when I try to do so.
What should I do to save it back to a csv file like the original?

 

[Erel]

You can save listOfArrays with StringUtils.SaveCSV.
If it doesn't work then please post the full error message from the logs (with the code I posted).

 

[Tim Chapman]

I ran the code you supplied with my addition of the su command at the bottom to save the CSV file.

    Dim listOfArrays As List
    listOfArrays.Initialize
    For Each item As Map In ListOfMaps
        Dim row(HeaderList.Size) As String
        For c = 0 To HeaderList.Size - 1
            row(c) = item.Get(HeaderList.Get(c))
        Next
        listOfArrays.Add(row)
    Next
    su.SaveCSV(File.DirRootExternal, "NewSaved" & FileName , "," , NewList)

Here is the log results:
main_loadcsvfromfile (B4A line: 366)
su.SaveCSV(File.DirRootExternal, "NewSaved" & Fil
java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.lang.String[]
at anywheresoftware.b4a.objects.StringUtils.SaveCSV2(StringUtils.java:107)
at anywheresoftware.b4a.objects.StringUtils.SaveCSV(StringUtils.java:100)
at uk.co.martinpearman.tabhostextrasdemo.main._loadcsvfromfile(main.java:1225)
at uk.co.martinpearman.tabhostextrasdemo.main._activity_create(main.java:408)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:179)
at uk.co.martinpearman.tabhostextrasdemo.main.afterFirstLayout(main.java:102)
at uk.co.martinpearman.tabhostextrasdemo.main.access$000(main.java:17)
at uk.co.martinpearman.tabhostextrasdemo.main$WaitForLayout.run(main.java:80)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

 

[Tim Chapman]

My bad. I had an error in the line I added. It referenced my previous list. Sorry.

 

[Tim Chapman]

Next Question:
Is there a way to keep the order of the saved csv list the same as the original order I loaded from the original CSV file?

 

[Tim Chapman]

I just realized that it is not in a different order. It is just that the first item is missing. I hope I can fix that.

 

[Erel]

Prefer For Each over regular For loops:

For Each cells() As String In ListFromFile
        Dim ItemMap As Map
        ItemMap.Initialize()
        For j = 0 To HeaderList.Size - 1
            ItemMap.Put(HeaderList.Get(j), cells(j))
        Next
        ListOfMaps.Add(ItemMap)
    Next

 

[Tim Chapman]

Thanks so much for your assistance! I am a new programmer. The majority of the code I posted came from my brother who is a 30 year veteran of python and databases. I am wrapping my head around how this stuff works. I will analyze what you gave me and figure out how it works.
Thanks again for your assistance!