How efficient is this method

[Polar Bear]

Hi,

 

Is there a more efficient way to check if an object can be converted to a number than this:

 

Function IsNumber(input As Object) As Boolean
   Dim out As Double
   Return Double.TryParse(input, 
           System.Globalization.NumberStyles.Number, 
           System.Globalization.NumberFormatInfo.CurrentInfo, out)
End Function

[bri189a]

Well you can always try converting the number in a try/catch. Errors being thrown are a performance hit though, but who knows, the double.TryParse may be using the same technique.

 

If you run some comparission tests let us know how it works out.

[PlausiblyDamp]

You could pass input as a string rather than object as .TryParse expects a string anyway.

[utilitaire]

Well you can always try converting the number in a try/catch. Errors being thrown are a performance hit though, but who knows, the double.TryParse may be using the same technique.

 

If you run some comparission tests let us know how it works out.

 

That's what I always do. I think this is quite performant, since:

 

1) as you said, Double.TryParse probably do a try/catch

 

2) the IsNumber() will probably be used most of the time with a number. Maybe 10% will generate a catch(). Depends how you use it, but If you actually expect a number, how many time the user will send a string that is non compatible? The user will send a number most of the time.