Dear All,

I am having a headache about checking if a variable is a number
(floating, double, and integer. Anything that is a numerical value).

If I use

if { [string is alnum "$_var1"] != 1}

The strings like "    "  or  "           "  (all blanks) will pass the
test, giving

So, is there a simple command to check if a variable is a numerical
number ?

And, is there also a simple command to check of a string is empty, or
just full of blanks ?

Thanks for the help in advance.

regards
S-Y. Chen

S-Y. Chen wrote:
> So, is there a simple command to check if a variable is a numerical
> number ?

[string is double -strict $var]

-- 
| Don Porter          Mathematical and Computational Sciences Division |
| donald.porter@nist.gov             Information Technology Laboratory |
| http://math.nist.gov/~DPorter/                                  NIST |
|______________________________________________________________________|

On Mar 10, 1:20=A0pm, "S-Y. Chen" <shenyeh_c...@hotmail.com> wrote:
> Dear All,
>
> I am having a headache about checking if a variable is a number
> (floating, double, and integer. Anything that is a numerical value).

Hi,

You can try something like if {[scan $myinput "%f%c" number
stopper]=3D=3D1} {bleh}

If $myinput is a number, scan should output 1; if it is whitespace it
should output -1; if it is nonnumerical garbage it should output 0;
and if it is garbage that begins with numerical characters, e.g.
-123abc, it should output 2.

--X