Get Substring - everything before certain char

Question

I m trying to figure out the best way to get everything before the - character in a string   Some example strings are below   The length of the string before - varies and can be any length  223232-1 jpg 443-2 jpg 34443553-5 jpg   so I need the value that s from the start index of 0 to right before -  So the substrings would turn out to be 223232  443  and 34443553

User · Answer

One way to do this is to use String Substring together with String IndexOf   int index   str IndexOf  -    string sub  if  index  gt   0        sub   str Substring 0  index     else       sub          handle strings without the dash     Starting at position 0  return all text up to  but not including  the dash

User · Answer

The LINQy way   String Concat   223232-1 jpg  TakeWhile c    c     -       But  you do need to test for null

User · Answer

Net Fiddle example  class Program       static void Main string   args                Console WriteLine  223232-1 jpg  GetUntilOrEmpty             Console WriteLine  443-2 jpg  GetUntilOrEmpty             Console WriteLine  34443553-5 jpg  GetUntilOrEmpty              Console ReadKey             static class Helper       public static string GetUntilOrEmpty this string text  string stopAt    -                 if   String IsNullOrWhiteSpace text                         int charLocation   text IndexOf stopAt  StringComparison Ordinal                if  charLocation  gt  0                                return text Substring 0  charLocation                                    return String Empty            Results   223232 443 34443553 344  34

User · Answer

Use the split function    static void Main string   args        string s    223232-1 jpg       Console WriteLine s Split  -   0        s    443-2 jpg       Console WriteLine s Split  -   0        s    34443553-5 jpg       Console WriteLine s Split  -   0     Console ReadKey        If your string doesn t have a - then you ll get the whole string

User · Answer

You can use regular expressions for this purpose  but it s good to avoid extra exceptions when input string mismatches against regular expression   First to avoid extra headache of escaping to regex pattern - we could just use function for that purpose   String reStrEnding   Regex Escape  -      I know that this does not do anything - as  -  is the same as Regex Escape              but it will make difference for example if character is        Then we need to match from begging of the string to string ending  or alternately if ending is not found - then match nothing   Empty string   Regex re   new Regex            reStrEnding     If your application is performance critical - then separate line for new Regex  if not - you can have everything in one line   And finally match against string and extract matched pattern   String matched   re Match str  Groups 1  ToString      And after that you can either write separate function  like it was done in another answer  or write inline lambda function  I ve wrote now using both notations - inline lambda function  does not allow default parameter  or separate function call   using System  using System Text RegularExpressions   static class Helper       public static string GetUntilOrEmpty this string text  string stopAt    -                 return new Regex            Regex Escape stopAt   Match text  Groups 1  Value           class Program       static void Main string   args                Regex re   new Regex        -            Func lt String  String gt  untilSlash    s    gt    return re Match s  Groups 1  ToString                Console WriteLine untilSlash  223232-1 jpg             Console WriteLine untilSlash  443-2 jpg             Console WriteLine untilSlash  34443553-5 jpg             Console WriteLine untilSlash  noEnding will result in empty string              Console WriteLine untilSlash                  Throws exception  Console WriteLine untilSlash null             Console WriteLine  443-2 jpg  GetUntilOrEmpty               Btw - changing regex pattern to         -     will allow to pick up either until  -  pattern or if pattern was not found - pick up everything until end of string

User · Answer

Things have moved on a bit since this thread started   Now  you could use  string Concat s TakeWhile  c    gt  c     -

User · Answer

String str    223232-1 jpg  int index   str IndexOf  -    if index  gt  0        return str Substring 0  index

User · Answer

Building on BrainCore s answer       int index   0         str    223232-1 jpg          Assuming we trust str isn t null      if  str Contains  -       true               int index   str IndexOf  -               if index  gt  0            return str Substring 0  index             else          return str

[c#] Get Substring - everything before certain char

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