    # Re: st: Re: summing up digits and comparing to a check digit

 From "Austin Nichols" To statalist@hsphsun2.harvard.edu Subject Re: st: Re: summing up digits and comparing to a check digit Date Wed, 15 Mar 2006 10:45:25 -0500

```I agree wholeheartedly with Michael Blasnik's opening caveat--was your
example 12050457 => 0+5+0+4+5+7=21/10=2+1 => check digit=1 supposed to
be 1050457 => 0+5+0+4+5+7=21/10=2+1 => check digit=1 by any chance?

As for his solution, it works well except when digits may be fewer
than 6 digits when turned into strings--I would replace his second
line with
replace x=substr("0000000",1,7-length(x))+x
assert length(x)==7
to make sure there are no odd cases.

. li m x c, noo clean

myvar         x   check
105059   0105059       0
2459   0002459       0
7102059   7102059       7

On 3/15/06, Michael Blasnik <michael.blasnik@verizon.net> wrote:
> I'm not sure I understand the problem -- one of your examples is an 8 digit
> number but you say you have 7 digit numbers.  Anyway, here is some "highly
>
> gen x=string(myvar)
> replace x="0"+x if length(x)==6
> gen
> check=mod(real(substr(x,2,1))+real(substr(x,3,1))+real(substr(x,4,1))+real(substr(x,5,1))+real(substr(x,6,1))+real(substr(x,7,1)),10)
>
> make sure to remove any line break that the email puts in the last line.

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