Regex to remove all special characters from string

Question

I m completely incapable of regular expressions  and so I need some help with a problem that I think would best be solved by using regular expressions   I have list of strings in C    List lt string gt  lstNames   new List lt string gt     lstNames add  TRA-94 23    lstNames add  TRA-42 101    lstNames add  TRA-109 AD     foreach  string n in lstNames         logic goes here that somehow uses regex to remove all special characters   string regExp    NO IDEA     string tmp   Regex Replace n  regExp           I need to be able to loop over the list and return each item without any special characters  For example  item one would be  TRA9423   item two would be  TRA42101  and item three would be TRA109AD    Is there a regular expression that can accomplish this for me   Also  the list contains more than 4000 items  so I need the search and replace to be efficient and quick if possible   EDIT  I should have specified that any character beside a-z  A-Z and 0-9 is special in my circumstance

User · Answer

tmp   Regex Replace n     W            w matches letters  digits  and underscores   W is the negated version

User · Answer

public static string Letters this string input        return string Concat input Where x   gt  char IsLetter x   amp  amp   char IsSymbol x   amp  amp   char IsWhiteSpace x

User · Answer

It really depends on your definition of special characters  I find that a whitelist rather than a blacklist is the best approach in most situations   tmp   Regex Replace n     0-9a-zA-Z            You should be careful with your current approach because the following two items will be converted to the same string and will therefore be indistinguishable    TRA-12 123   TRA-121 23

User · Answer

a-zA-Z0-9  is a character class matches any non-alphanumeric characters   Alternatively     w d  does the same thing   Usage   string regExp       w d    string tmp   Regex Replace n  regExp

User · Answer

This should do it     a-zA-Z0-9    Basically it matches all non-alphanumeric characters

User · Answer

If you don t want to use Regex then another option is to use  char IsLetterOrDigit   You can use this to loop through each char of the string and only return if true

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For my purposes I wanted all English ASCII chars  so this worked   html   Regex Replace html      x00- x80

User · Answer

You can use   string regExp      W     This is equivalent to Daniel s    a-zA-Z0-9     W matches any nonword character  Equivalent to the Unicode categories    p Ll  p Lu  p Lt  p Lo  p Nd  p Pc

User · Answer

Depending on your definition of  special character   I think    a-zA-Z0-9   would probably do the trick  That would find anything that is not a small letter  a capital letter  or a digit

[c#] Regex to remove all special characters from string?

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