Android Question How to replace null values with zero's in double array?

[RB Smissaert]

This sounds like a simple thing, but not managed it so far.
What would be the best way to do this?

RBS

 

[stevel05]

How are you creating the double array?

 

[RB Smissaert]

How are you creating the double array?

Mainly from SQLite.
I know I can avoid the null values at source, but I still need to check and clear from the array.

RBS

 

[stevel05]

If you can't change the source to exclude nulls, then I think you will have to cast the array initially to an array of object to do the conversion, then create the Double array, replacing the nulls as you go.

'ObjArr is an array of Object read from the database
Dim DblArr(ObjArr.Length) As Double
For i = 0 To ObjArr.Length - 1
    Dim O As Object = ObjArr(i)
    If O = Null Then
        DblArr(i) = 0
    Else
        DblArr(i) = O
    End If
Next

 

[OliverA]

How are you creating the double array?

Mainly from SQLite.

I feel dumb. How is this achieved?

 

[RB Smissaert]

I feel dumb. How is this achieved?

Copy ResultSet values to double array.

RBS

 

[klaus]

Maybe this:

str = Curs.GetString2(col)
If str <> Null Then
   dd = Curs.GetDouble2(col)
Else
   dd = 0
End If

 

[RB Smissaert]

Maybe this:

str = Curs.GetString2(col)
If str <> Null Then
   dd = Curs.GetDouble2(col)
Else
   dd = 0
End If

Thanks, that seems to work indeed.

RBS

 

[RB Smissaert]

Maybe this:

str = Curs.GetString2(col)
If str <> Null Then
   dd = Curs.GetDouble2(col)
Else
   dd = 0
End If

This all has to do with the table sorting. Null values seriously mess up the Double QuickSort.

RBS

 

[Mahares]

If str <> Null Then

I usually do not argue with klaus. Shouldn't this be:

If str <> Null and isnumber(str) Then

 

[klaus]

Sure, it's more universal.
But, it seems that he expects a Double therefore the 'limited' code works.
Because, I hope so, the type check was done before.

 

[Star-Dust]

Sure, it's more universal.
But, it seems that he expects a Double therefore the 'limited' code works.
Because, I hope so, the type check was done before.

I usually do not argue with klaus. Shouldn't this be:

If str <> Null and isnumber(str) Then

I also normally don't contradict @klaus, but I think this time I disagree with his solution.
If you use this statement str = Curs.GetString2(col) and the value is null str does not become null but sometimes str = "null" as a string, I would do so

str = Curs.GetString2(col)
If str <> Null And str<>"null" Then
     If isnumber(str)  Then
     End IF
End IF

 

[LucaMs]

I also normally contradict @klaus, but I think this time I disagree with his solution.
If you use this statement str = Curs.GetString2(col) and the value is null str does not become null but sometimes str = "null" as a string, I would do so

str = Curs.GetString2(col)
If str <> Null And str<>"null" Then
     If isnumber(str)  Then
     End IF
End IF

The check can be done in a single line:

str = Curs.GetString2(col)
If str <> Null And str <> "null" And IsNumber(str) Then
'
End IF

 

[Star-Dust]

The check can be done in a single line:

str = Curs.GetString2(col)
If str <> Null And str <> "null" And IsNumber(str) Then
'
End IF

I'm not sure that isNumber with a null value doesn't generate a runtime error

 

[OliverA]

B4X short circuits logical evaluations. The first false expression in an and expression stops checking and therefore does not evaluate any other expressions in the statement.

 

[Mahares]

Since the OP retrieves data from a SQLite table, shouldn't he try to avoid the presence of a null in any of his output by simply invoking the Ifnull function like this or am I slow to catch up to this debate:

ifnull(mycol, 0) as col

 

[Star-Dust]

@Star-Dust: I think you mean to say: 'I also normally DO NOT contradict @klaus, '

Right, a typing mistake