Maximum value as a number and not string

[LePot]

Hallo,

I calculated the maximum value of a channel. The next step is to use that value for further calculation. My problem is that i cant use that value as a number. Its just a string. I tried it with

ChnPropGet so that i got the number. But I  cant use it for calculations. Does anybody have an idea how i can solve that problem?

I attach a screenshot of my Skript. I use the german version of DIAdem 12.

Thanks for help...

[Pesmith8]

LePot

The cdbl command will convert to double subtype, from which you can do calculations.

Paul

I have found that using the first char of a variable name for type, helpful. given the untyped nature of VBscript.

as in:

i for integer

d for double

s for string

[AndreasH_Ha · Accepted solution]

Hello LePot,

the properties.Value function returns teh property in its native type. If you access the maximum property of a channel it will return the value as a floating point number. You can check this by running the following script:

(The script assumes that teh example dataset is load which has a group number 3 with a channel named "Res_Schall_1". But your channels should give you the same result with the messagebox showing "double"

Dim Maximum
Maximum = Data.Root.ChannelGroups(3).Channels("Res_Schall_1").Properties("minimum").Value
MsgBox(TypeName(Maximum)) 

Should you ever want to convert from a number represented as a string, be careful when using "CDbl". This VBScript function assumes that the number is formatted using the locale setting from oyur OS, especially the decimal delimiter (being "." or ",") . If the setting in the OS doesn't match the way teh number was converted into a string, you have a problem. This is why DIAdem offers str() to go from a number to s string and Val() to go the opposite direction. Using CDbl can create rellay mean errors which are hard to detect.

Andreas

[Pesmith8]

Hello LePot

Very good posts to your question have been made.

I also like Val and str,  Another one that is useful is "IsNumeric"

It can be used to test if a value in a numeric and then appropriate action taken. 

Like 

dim dNum

if (isnumeric(Value)) then

  dNum = Val(Value)

end if

This allow you to test that a string is a actual number before a conversion is tried.

There are other "is" functions that are also very useful.   Especially the "isNull"  as you can not do a comparision to a null value, you can only use the isnull function.

Paul

[Philipp_Kost]

Hi everybody,

I havent realized this problem.

when i check this cahnnelproperty  I get a true:

call msgbox( isnumeric(Data.Root.ChannelGroups(1).Channels("Geschwindigkeit").Properties("maximum").Value) )

If there wouldn't be a true you normaly can use this string as a number for operations.

dim a : a = "3"
dim b
call msgbox( a+2 ) ' this returns a 5

Of course a real typecast and check is the best way to prevent from errors.

Kind Regards,

Philipp K.

AE  NI Germany

[LePot]

Thank u all for help. Actually u are right. Its already a double. So it works.

But at least i know how to figure out what kind of type are my variable now and I know how to convert them.