select case with non integer numbers

[vb_student]

Hello
I have got a select case structure with non integer values, it goes like this

select case power

case 0.001
'statements
case 1
'statements

case 2
'statements

case 20.001
'statements

case 40
'statements

case 40.001
'statements

case 60
'statements

case 60.001
'statements

end select

however my case structure does not work with non integer values like the 0.001, 40.001, 60.001

i tried with declaring power as a double like so

Dim power As Double

but that did not work either

[sciguyryan]

I suppose you could create a temporary variable to make the numbers strings and check it that way.

Example:

Select Case CStr(power)
    Case "0.001"
        ' Statements
    Case "1"
        ' Statements
    Case "2" 
        ' Statements
    Case "20.001"
        ' Statements
    Case "40"
        ' Statements
    Case "40.001"
        ' Statements
    Case "60"
        ' Statements
    Case "60.001"
        ' Statements
End Select

Cheers,


RyanJ

[trisuglow]

Select Case will work with strings.

Dim power as Double
    Dim pString as String
 
    pString = power
    Select Case pString
'
'
'

[vb_student]

is there no way to check for non integer values in a select structure then?

[trisuglow]

is there no way to check for non integer values in a select structure then?

No, I don't believe there is. However, here's another thought. Why not multiply your values by 1000 for the Select statement?

Select Case power * 1000
    Case 1  'power = 0.001
        ' Statements
    Case 1000 'power = 1
        ' Statements
    Case 2000 'power = 2
        ' Statements
    Case 20001 'power = 20.001

[Supremus]

G'day,

OPen a new form and place a text box on it and try this.

Private Sub Text1_KeyPress(KeyAscii As Integer)
  If KeyAscii = 13 Then
  
    Select Case Text1.Text
    Case 1:
      MsgBox "1 was entered"
    
    Case 0.01
      MsgBox "0.01 was entered"
    
    Case Else
       MsgBox "Something else was entered"
     End Select
  End If 
End Sub

[Supremus]

G'day,

Not sure wheat went wrong with previous post.

Open a new form with a textbox called text1 on it and add the following code.


Private Sub Text1_KeyPress(KeyAscii As Integer)

If KeyAscii = 13 Then

Select Case Text1.Text

Case 1:
MsgBox "1 was entered"

Case 0.01
MsgBox "0.01 was entered"

Case Else
MsgBox "Something else was entered"

End Select

End If

End Sub

[vb_student]

thanks for all the suggestions

supremus, i think your suggestion works cause it probably takes it in and comapres the text. i like the multiply by 1000. elegant !!

it's a shame that the case structure does not take into account fractional numbers

[trisuglow]

Word of warning:

Supremus' method treats "1" and "1.0" as different values. This is not a problem with the x1000 method I suggested earlier in the thread. However, pick whichever solution works best for you.

[vb_student]

i did the multiply by 1000 method, it has the value 60001 (checked it in the immediate window) but still drops through the case structure

i will try out the string converstion method now

[vb_student]

this is interesting
the following structure works

  powstring = power

Select Case powstring
    Case "0.001"
'statements

case 1
'statements

case "60.001"
'statements

end select

but not this code

  powstring = power

Select Case powstring
Case 0.001
'statements

case 1
'statements

case 60.001
'statements

end select

[trisuglow]

That's strange that the x1000 method didn't work for you. This test code worked fine for me for all values.

Private Sub Command1_Click()
  Dim power As Single
  power = Val(InputBox("Enter value for power"))
  Select Case power * 1000
      Case 1
          Debug.Print "0.001"
      Case 1000
          Debug.Print "1"
      Case 2000
          Debug.Print "2"
      Case 20001
          Debug.Print "20.001"
      Case 40000
          Debug.Print "40"
      Case 40001
          Debug.Print "40.001"
      Case 60000
          Debug.Print "60"
      Case 60001
          Debug.Print "60.001"
  End Select
End Sub

[PilgrimPete]

I wasn't aware that Select Case didn't work with doubles...
I tried this, and it works:

Private Sub Command1_Click()
    CheckValue 0.001
    CheckValue 0.002
    CheckValue 0.003
End Sub
 
Private Sub CheckValue(ByVal x As Double)
    Select Case x
    Case 0.001
        MsgBox "You passed 1E-3"
    Case 0.002
        MsgBox "You passed 2E-3"
    Case Else
        MsgBox "You passed " & CStr(x)
    End Select
End Sub

Where are your values coming from, can you be sure of their precision?

[szlamany]

this is interesting
the following structure works

  powstring = power

Select Case powstring
    Case "0.001"
'statements

case 1
'statements

case "60.001"
'statements

end select

but not this code

  powstring = power

Select Case powstring
Case 0.001
'statements

case 1
'statements

case 60.001
'statements

end select

Floating point (single and double) are evil.

You just fell right into the reason for it.

DISPLAY a DOUBLE value and you see one thing - compare it in an IF or SELECT/CASE and it all of a sudden doesn't work.

Something that might display at 4.5 is really stored as 4.499999999999999999

That's the way DOUBLE works.

Why can't you use CURRENCY? It doesn't have this problem and the SELECT/CASE will all of a suddent work beautifully.

If you need double, change the CASE's to a RANGE - not an exact value - a bit below and a bit above the value you are trying to CASE on.

[vb_student]

hey in another part of my code, power with 0.001 works OK

is this some sort of idiosynchracy in VB?

i had nto decalred the power in that module too. is it because of that, in the module where it was not working i had dxeclared it as a double.

[szlamany]

You must understand that DOUBLE will give you these inconsistent results.

Do you need to store your values as DOUBLE?

Why doesn't the CURRENCY datatype work for you - it precise and doesn't have the issues that DOUBLE does.

[vb_student]

it somehow works now with double, i will leave it at that and if the big guy wants me to clean up the code, i will do it later

what is the difference between double and currency?

currency sounds something to do with dollars, pounds and yen not fractional numbers.

[szlamany]

Currency is a datatype that allows four digits after the decimal point.

It's actually a long, with an "implied" decimal - so it has the accuracy of long but the fake decimal point works for you...

[vb_student]

thanks for telling me about currencies

i just tried longs elsewhere in my code and they did not work for fractions

there does not seem to be a correspondence between variable types in c and VB

doubles and longs used to accept fractional parts in c but they dont in VB, correct?

[szlamany]

I do not know C - I cannot imagine a LONG ever accepting a decimal fractional part...

CURRENCY is a special "made-up" type that is really a LONG, but with an implied decimal - it's nice and accurate.

[Mc Brain]

No, I don't believe there is. However, here's another thought. Why not multiply your values by 1000 for the Select statement?

Select Case power * 1000
    Case 1  'power = 0.001
        ' Statements
    Case 1000 'power = 1
        ' Statements
    Case 2000 'power = 2
        ' Statements
    Case 20001 'power = 20.001

Yes you can. This code works.

Option Explicit
 
Private Sub Form_Load()
    SelectCase 0.01
    SelectCase 0.02
    SelectCase 1
    SelectCase 2
End Sub
 
Private Sub SelectCase(dblNumber As Double)
    Select Case dblNumber
        Case 0.01
            Debug.Print "0.01"
        Case 0.02
            Debug.Print "0.02"
        Case 1
            Debug.Print "1"
        Case 2
            Debug.Print "2"
    End Select
End Sub