Regular expression for validating names and surnames

Question

Although this seems like a trivial question  I am quite sure it is not     I need to validate names and surnames of people from all over the world  Imagine a huge list of miilions of names and surnames where I need to remove as well as possible any cruft I identify  How can I do that with a regular expression  If it were only English ones I think that this would cut it     a-z -       However  I need to support also these cases    other punctuation symbols as they might be used in different countries  no idea which  but maybe you do   different Unicode letter sets  accented letter  greek  japanese  chinese  and so on  no numbers or symbols or unnecessary punctuation or runes  etc   titles  middle initials  suffixes are not part of this data names are already separated by surnames  we are prepared to force ultra rare names to be simplified  there s a person named     in existence  but it doesn t make sense to allow that character everywhere  Use pragmatism and good sense   note that many countries have laws about names so there are standards to follow   Is there a standard way of validating these fields I can implement to make sure that our website users have a great experience and can actually use their name when registering in the list   I would be looking for something similar to the many  email address  regexes that you can find on google

User · Answer

This somewhat helps     a-zA-Z     a-zA-Z       -

User · Answer

This one should work    A-Z  1   a-z -         s     Add some special characters if you need them

User · Answer

I would think you would be better off excluding the characters you don t want with a regex  Trying to get every umlaut  accented e  hyphen  etc  will be pretty insane  Just exclude digits  but then what about a guy named  George Forman the 4th   and symbols you know you don t want like       or what have you  But even then  using a regex will only guarantee that the input matches the regex  it will not tell you that it is a valid name  EDIT after clarifying that this is trying to prevent XSS  A regex on a name field is obviously not going to stop XSS on it s own  However  this article has a section on filtering that is a starting point if you want to go that route   http   tldp org HOWTO Secure-Programs-HOWTO cross-site-malicious-content html  s    lt   gt               amp      g

User · Answer

I don   t think that   s a good idea  Even if you find an appropriate regular expression  maybe using Unicode character properties   this wouldn   t prevent users from entering pseudo-names like John Doe  Max Mustermann  there even is a person with that name   Abcde Fghijk or Ababa Bebebe

User · Answer

You could use the following regex code to validate 2 names separeted by a space with the following regex code     A-Za-z  -      A-Za-z  -       or just use      lower       a-z  -        upper      A-Z  -        alpha       A-Za-z  -        alnum       A-Za-z  -  0-9

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BTW  do you plan to only permit the Latin alphabet  or do you also plan to try to validate Chinese  Arabic  Hindi  etc    As others have said  don t even try to do this  Step back and ask yourself what you are actually trying to accomplish  Then try to accomplish it without making any assumptions about what people s names are  or what they mean

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I sympathize with the need to constrain input in this situation  but I don t believe it is possible - Unicode is vast  expanding  and so is the subset used in names throughout the world    Unlike email  there s no universally agreed-upon standard for the names people may use  or even which representations they may register as official with their respective governments  I suspect that any regex will eventually fail to pass a name considered valid by someone  somewhere in the world   Of course  you do need to sanitize or escape input  to avoid the Little Bobby Tables problem  And there may be other constraints on which input you allow as well  such as the underlying systems used to store  render or manipulate names  As such  I recommend that you determine first the restrictions necessitated by the system your validation belongs to  and create a validation expression based on those alone  This may still cause inconvenience in some scenarios  but they should be rare

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Steps     first remove all accents  apply the regular expression   To strip the accents   private static string RemoveAccents string s        s   s Normalize NormalizationForm FormD       StringBuilder sb   new StringBuilder        for  int i   0  i  lt  s Length  i                  if  CharUnicodeInfo GetUnicodeCategory s i      UnicodeCategory NonSpacingMark  sb Append s i              return sb ToString

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I would just allow everything  except an empty string  and assume the user knows what his name is   There are 2 common cases    You care that the name is accurate and are validating against a real paper passport or other identity document  or against a credit card  You don t care that much and the user will be able to register as  Fred Smith   or  Jane Doe   anyway    In case  1   you can allow all characters because you re checking against a paper document   In case  2   you may as well allow all characters because  123 456  is really no worse a pseudonym than  Abc Def

User · Answer

This one worked perfectly for me in JavaScript    a-zA-Z    s -   a-zA-Z    s -   a-zA-Z    Here is the method  function isValidName name        var found   name search    a-zA-Z    s -   a-zA-Z    s -   a-zA-Z           return found  gt  -1

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It s a very difficult problem to validate something like a name due to all the corner cases possible   Corner Cases   Anything anything here   Sanitize the inputs and let them enter whatever they want for a name  because deciding what is a valid name and what is not is probably way outside the scope of whatever you re doing  given the range of potential strange - and legal names is nearly infinite   If they want to call themselves Tricyclopltz 2-Glockenschpiel  that s their problem  not yours

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A very contentious subject that I seem to have stumbled along here  However sometimes it s nice to head dear little-bobby tables off at the pass and send little Robert to the headmasters office along with his semi-colons and SQL comment lines --   This REGEX in VB NET includes regular alphabetic characters and various circumflexed european characters   However poor old James Mc Tristan-Smythe the 3rd will have to input his pedigree in as the Jim the Third    lt asp RegularExpressionValidator ID  RegExValid1  Runat  server                      ErrorMessage  ERROR  Please enter a valid surname lt br  gt   SetFocusOnError  true  Display  Dynamic                      ControlToValidate  txtSurname  ValidationGroup  MandatoryContent                      ValidationExpression    A-Za-z  - p L  p Zs  p Lu  p Ll        gt

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I ll try to give a proper answer myself   The only punctuations that should be allowed in a name are full stop  apostrophe and hyphen  I haven t seen any other case in the list of corner cases   Regarding numbers  there s only one case with an 8  I think I can safely disallow that   Regarding letters  any letter is valid   I also want to include space   This would sum up to this regex      p L      -      This presents one problem  i e  the apostrophe can be used as an attack vector  It should be encoded   So the validation code should be something like this  untested    var name   nameParam Trim    if   Regex IsMatch name      p L     -            throw new ArgumentException  nameParam    name   name Replace        amp  39         amp apos  does not work in IE   Can anyone think of a reason why a name should not pass this test or a XSS or SQL Injection that could pass     complete tested solution  using System  using System Text RegularExpressions   namespace test       class MainClass               public static void Main string   args                        var names   new string    Hello World                     John                    Jo  o                                                                                                                                        Te   e a                                                                                                                                                           D Addario                    John-Doe                    P A M                       --                     lt xss gt                                                    foreach  var nameParam in names                                Console Write nameParam                       var name   nameParam Trim                    if   Regex IsMatch name       p L  p M      -                                             Console WriteLine  fail                        continue                                    name   name Replace        amp  39                     Console WriteLine name

[regex] Regular expression for validating names and surnames?

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