Yes my problem implied manipulation of integers only, although the
discussion about decimals could be useful for someone else.
Thanks a lot, I am amazed and grateful
Lia
Nick Cox wrote:
The limitations of the -mod()- function
given fractional parts are indeed important.
FWIW, Tom Steichen and I wrote this up at
http://www.stata.com/support/faqs/data/mod.html
I was presupposing manipulations of integers
only, as the context implies.
Nick
n.j.cox@durham.ac.uk
Richard Atkins
Rather than use the mod function I would recommend converting all your
values to formatted strings using the =string(varname, format) command
prior to extracting the digits.
In general the mod function works well but I have come across datasets
where values that displayed in tables and lists as (for example) 0.7
produced a '6' when I tried to extract the 'tenths' digit using
mod(int(varname*10),10). It turned out that the floating point
representation of this value in the dta file was actually
0.69999999 so
the mod function gave me exactly what I asked for rather than what I
actually wanted.
Some examples of extracting digits in this way are available in my
digit preference functions at
http://www.richardatkins.co.uk/statistics/statabits.htm
n.j.cox@durham.ac.uk 03/15/06 3:04 pm >>>
-pnrcheck- from SSC covers the Swedish case.
In this case, look _inside_ the program
for some ideas. String functions are not
the only way. -mod()- is also useful.
The authors of -pnrcheck- are two Italians
and a Welshman, just who you would expect
to be working on Swedish identifiers.
Nick
n.j.cox@durham.ac.uk
Lia Orfei
I have a variable that contains 7-digit numbers; the first
digit is the
remainder of the sum of the last six digits divided by 10
(check digit)
example: 1030332 => 0+3+0+3+3+2=11/10=1+1 => check digit=1
12050457 => 0+5+0+4+5+7=21/10=2+1 => check digit=1
and so on.
Now I want to assess whther the check digit is correct for each
entry.
How do I calculate the partial sum of the contents of this variable?
Extra challenge: some of the numbers sum up to 10, 20 etc so
the check
digit is actually 0 and it does not appear in the data for
some reason
(example 50456 is correct becasue 5+0+4+5+6=20 so the remainder is
0).
Any ideas?? I was thinking about using the string functions.
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