VAL keyword

[taximania]

Here's a starter for you. If you haven't done it already.

Sub VAL(s)
temp = ""
temp2=0
flag = 0
If StrLength(s) = 0 Then
    Return 0
Else
    len = StrLength(s)
    For a = 0 To len -1
        If IsNumber(StrAt(s,a)) Then
            temp = temp & StrAt(s,a)
        Else
            If StrAt(s,a) = "." Then
                If flag = 0 Then
                    flag = 1
                    temp = temp & "."
                End If
            End If
        End If
    Next
    If temp = "" OR temp = "." Then
        Return 0
    Else
        temp2 = temp2 + temp
        Return temp2
    End If
End If
End Sub

Returns 0 for no number found.
The first '.' found is treat as a decimal point. All others are ignored.
Trims excessive leading and trailing '0's.

[SarahWard]

That's pretty neat, Taximania, thanks.

Saves me having to switch my brain on! (It lasts longer in standby mode.)

Sarah

[taximania]

Just trying to help the Basic4ppc community if I can

[beacon]

I agree that it would be very useful.

Here is a typical use for Val():

A User types a time into a textbox, say "18:36".

I extract the hours portion using stringsex.mid to give a string called (say) MyHours holding "18".

Now I can code

if val(MyHours)<12 then
.......
end if

See how the computation is treating the string "18" as the value 18.

Voila!

I use this Val() function in VB6 a lot.

Is this helpful?

[derez]

It can be done like this also without the Val sub:
if MyHours + 0 < 12 then... because the operation on the string converts it to a number.

[agraham]

Originally Posted by beacon

See how the computation is treating the string "18" as the value 18.

As Basic4ppc is untyped, or more accurately does automatic type conversion, a numeric string is treated the same a numeric literal so Val is not needed in this case.

[mjcoon]

Originally Posted by agraham

As Basic4ppc is untyped, or more accurately does automatic type conversion, a numeric string is treated the same a numeric literal so Val is not needed in this case.

But there is a trap there that I fell into a few days ago. I was wishing to "correct" a "North" bearing value that is delivered by my GPS via NMEA as "360.0" which is not a valid value. (The GPS actually prevents me from entering that value via its user interface!)

So I wrote:

If headingDirection = 360 Then headingDirection = 0

What was in my head was that Basic4PPC would convert to numeric for the comparison but it doesn't and finds that "360.0" is not equal to 360. I would have used a Val() if Basic4PPC had one.

Mike.

[agraham]

Originally Posted by mjcoon

What was in my head was that Basic4PPC would convert to numeric for the comparison but it doesn't and finds that "360.0" is not equal to 360.

Yes, I'm afraid that the Basic4ppc rule for logical comparisons is not documented but it seems that all comparisons are made as strings and typed variables are converted to a string for the comparison.

I would have used a Val() if Basic4PPC had one.

Int or Abs would work in your situation.

As an aside there is an "interesting" difference between .NET and Java(Android) that I have encountered. In .NET a Double and an Integer containing the same integer value both convert to identical strings. e.g. "360". In Java the Double conversion always ends with a decimal place, even for an integer value so the resulting strings are not the same. e.g "360.0" for a Double and "360" for an Integer.

[ceaser]

Hi

How abot having a little as follows:

'S = String to be checked for a number

N=""
For i=0 to StrLength(s)
i1=Asc(SubString(S,i,1))
if i1=46 or (i1>=48 and i1<=57) then
N=N & i1
end if
Next i
Msgbox(N)

I have not checked it, but along this line should work.

Regards
Michael

[mjcoon]

Originally Posted by ceaser

'S = String to be checked for a number ...

It would be (slightly!) interesting to know if the built-in automatic conversions can cope with all the number representations that can be generated by the Format() function... (Scientific notation; "." and "," separators; etc.)

Mike.