Ensuring numeric input

[Dennis Brown]

Try using isNumber --from the docs:

the isNumber of value
isNumber(value)

isNumber(8) -- returns true
isNumber(1+5) -- returns true
isNumber(foo) -- returns false

Dennis

On Oct 26, 2005, at 8:34 PM, Michael J. Lew wrote:

> How can I prevent users from being able to make non-number values  
> in a field? Simply preventing non-numeric keys is not enough  
> because I need to prevent things that use characters that are in  
> valid numbers to make non-numbers like 1.2.3 or -1.2-3.
>
> I thought it would be relatively easy, but it might not be. Here is  
> the field script of a surprisingly complicated attempt:
>
> on keydown thekey
>   if theKey is in "0123456789-." then --may be an allowable input
>     -- but I still need to check whether the result would be a  
> valid number.
>     put value(the selectedLine) into thisLine --current number
>     put length(thisLine) into thisLineLen
>     put the selectedCHunk into sc --returns character locations  
> from start of field
>        --Need to find where the current line starts
>     put offset(thisLine,me,min(0,word 2 of sc-thislinelen)) into  
> thisLineStart
>     --The characters to skip bit is an attempt to prevent the  
> offset function
>     --  from returning a match to an earlier line in the field.
>     --  It needs the min function to prevent negative values.
>        --Now see if the input would make a non-numeric result
>     --First find where the selection point is in the line
>     put word 2 of sc +1 - thisLineStart into theSelectionStartChar
>     put word 4 of sc +1 - thisLineStart into theSelectionEndChar
>     --I don't know why I had to add one to the values...
>     put thisLineStart & return & theSelectionStartChar &&  
> theSelectionEndCHar
>     --Now test the input in the relevant place
>     put theKey into char theSelectionStartChar to  
> theSelectionEndChar of thisLine
>        --next line to help debugging
>     --put  thisLine & return & thisLineStart & return &  
> theSelectionStartChar && theSelectionEndChar
>        if thisLine & "0" is a number then --should be OK
>       --Needs the appended zero to allow a line to start with a  
> decimal point.
>       pass KeyDown
>     end if
>   end if
> end keydown
>
>
> It seems to work, but it's an extraordinarily long and winding road  
> to get to a simple end-point. What am I missing?
>
> Thanks,
> Michael
>
> -- 
> Michael J. Lew
>
> Senior Lecturer
> Department of Pharmacology
> The University of Melbourne
> Parkville 3010 put "-1" is a number
> Victoria
> Australia
>
> Phone +613 8344 8304
>
> **
> New email address: michaell at unimelb.edu.au
> **
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