In one of the projects at my work, I got task to verify some data (in migration process from old system to new one); one of the fields was Chilean RUT (Rol Único Tributario) or Tax Identification Number.
The RUT has 8 digits plus a validation number or letter (xx.xxx.xxx-z) and algorithm for verification (as per my knowledge) is as follows:
- Remove all characters except digits and last char which can be digit or letter “K”
- Pad with zeros (“0”) string until it is exactly 9 symbols long
- Multiply, from left to right, first 8 digits with following factors: 3, 2, 7, 6, 5, 4, 3, 2 and sum those results (let’s call it total)
- Find difference: 11 – (total % 11) (let’s call it rest)
- Determine control char by:
-
5.1 If rest = 11, than control char “0” (zero)
5.2 If rest = 10, than control char “K”
5.3 Otherwise, rest is control char - If the original control char (9th char) is equal to calculated control char, RUT is valid.
C# code for this could be like this:
/// <summary> /// Routine for checking of RUT correctness /// </summary> /// <param name="rut">RUT to check</param> /// <returns>true if RUT is valid</returns> /// <remarks>Only numbers and optional "K" at the end of string are expected /// </remarks> public static bool IsRutOk(string rut) { const string RutRegex = "[0-9]+K?"; Regex RegExRut = new Regex(RutRegex, RegexOptions.Compiled | RegexOptions.IgnoreCase); int[] coefs = {3, 2, 7, 6, 5, 4, 3, 2}; // In case that rut is padded with spaces rut = rut.Trim().ToUpperInvariant(); if (!RegExRut.IsMatch(rut)) { return false; } if (rut.Length > 9) { return false; } // If shorter than 9 characters (8 + control char) ... while (rut.Length < 9) { rut = "0" + rut; } int total = 0; for (int index = 0; index < rut.Length - 1; index++) { char curr = rut.Substring(index, 1).ToCharArray()[0]; total += coefs[index]*(curr - '0'); } int rest = 11 - (total%11); if (rest == 11) rest = 0; if ((rest == 10) && rut.EndsWith("K")) { return true; } if (rut.Substring(rut.Length - 1, 1).ToCharArray()[0] == ('0' + rest)) { return true; } return false; }
You could ask me and Deki for the function or you could have written it earlier. At least one of us would not have to do it then
Good to know for next time
Hej man, otkud ti da se bavis cileanskim rutom?! :-))
Posao ne bira
Истио се и ја питам
This routine does not work and does not produce verifiable result.
If you run RUT by it and then attempt to verify it against known RUT databases – it is hit or miss like 50/50 chances.
Do not waste your time on integrating this one to your app.
This is rather bold statement, especially 50/50 part.
Do you have some examples (of not working well)?
Regards,
Dejan
HOW LONG IS A CHILEAN RUT NUMBER VALID?
Your code doesn’t do very well against this RUT generator.
http://tools.optionti.com/app/RutGenerator/
Ok, tips to fix this code and make it more reliable.
Small tip
while (rut.Length < 9) { rut = "0" + rut; } is the same thing as
rut = rut.PadLeft(9, '0');
Please always use pad left rather than writing your own.
In your code you have –
(rut.Substring(rut.Length – 1, 1).ToCharArray()[0] == ('0' + rest))
this is very odd and unreliable for comparing the last character. the below is much simpler and really cleans up a lot of error cases
if (rut.Substring(rut.Length – 1, 1) == rest.ToString())
While it doesn't seem to affect the functionality I find your handling of chars as ints in your for loop a little odd. I haven't touched it but I wonder if its better to simply treat each character as an int and do your math that way.
thanks for code, I wrote it for C++ based on yours and tested against RUT generator , is the only place on web where I found such information / constantin Romania