Matching strings with wildcard

Question

I would like to match strings with a wildcard      where the wildcard means  any   For example    X   string must end with X X    string must start with X  X    string must contain X   Also  some compound uses such as    X YZ    string contains X and contains YZ X YZ P   string starts with X  contains YZ and ends with P    Is there a simple algorithm to do this   I m unsure about using regex  though it is a possibility    To clarify  the users will type in the above to a filter box  as simple a filter as possible   I don t want them to have to write regular expressions themselves   So something I can easily transform from the above notation would be good

User · Answer

A wildcard   can be translated as    or     regex pattern   You might need to use a singleline mode to match newline symbols  and in this case  you can use   s  as part of the regex pattern   You can set it for the whole or part of the pattern   X     gt    X  s       X    gt      s    X   X     gt      s   X     X YZ     gt      s   X  YZ    X YZ P    gt      s X  YZ  P

User · Answer

Using of WildcardPattern from System Management Automation may be an option   pattern   new WildcardPattern patternString   pattern IsMatch stringToMatch     Visual Studio UI may not allow you to add System Management Automation assembly to References of your project  Feel free to add it manually  as described here

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X YZ    string contains X and contains YZ      X  YZ    X YZ P   string starts with X  contains YZ and ends with P      X  YZ  P

User · Answer

public class Wildcard       private readonly string  pattern       public Wildcard string pattern                 pattern   pattern             public static bool Match string value  string pattern                int start   -1          int end   -1          return Match value  pattern  ref start  ref end              public static bool Match string value  string pattern  char   toLowerTable                int start   -1          int end   -1          return Match value  pattern  ref start  ref end  toLowerTable              public static bool Match string value  string pattern  ref int start  ref int end                return new Wildcard pattern  IsMatch value  ref start  ref end              public static bool Match string value  string pattern  ref int start  ref int end  char   toLowerTable                return new Wildcard pattern  IsMatch value  ref start  ref end  toLowerTable              public bool IsMatch string str                int start   -1          int end   -1          return IsMatch str  ref start  ref end              public bool IsMatch string str  char   toLowerTable                int start   -1          int end   -1          return IsMatch str  ref start  ref end  toLowerTable              public bool IsMatch string str  ref int start  ref int end                if   pattern Length    0  return false          int pindex   0          int sindex   0          int pattern len    pattern Length          int str len   str Length          start   -1          while  true                        bool star   false              if   pattern pindex                                        star   true                  do                                       pindex                                      while  pindex  lt  pattern len  amp  amp   pattern pindex                                     end   sindex              int i              while  true                                int si   0                  bool breakLoops   false                  for  i   0  pindex   i  lt  pattern len  amp  amp   pattern pindex   i          i                                          si   sindex   i                      if  si    str len                                                return false                                            if  str si      pattern pindex   i                                                 continue                                            if  si    str len                                                return false                                            if   pattern pindex   i          amp  amp  str si                                                        continue                                            breakLoops   true                      break                                    if  breakLoops                                        if   star                                                return false                                            sindex                        if  si    str len                                                return false                                                          else                                       if  start    -1                                                start   sindex                                            if  pindex   i  lt  pattern len  amp  amp   pattern pindex   i                                                        break                                            if  sindex   i    str len                                                if  end  lt   start                                                        end   str len                                                    return true                                            if  i    0  amp  amp   pattern pindex   i - 1                                                        return true                                            if   star                                                return false                                            sindex                                                sindex    i              pindex    i              if  start    -1                                start   sindex                                     public bool IsMatch string str  ref int start  ref int end  char   toLowerTable                if   pattern Length    0  return false           int pindex   0          int sindex   0          int pattern len    pattern Length          int str len   str Length          start   -1          while  true                        bool star   false              if   pattern pindex                                        star   true                  do                                       pindex                                      while  pindex  lt  pattern len  amp  amp   pattern pindex                                     end   sindex              int i              while  true                                int si   0                  bool breakLoops   false                   for  i   0  pindex   i  lt  pattern len  amp  amp   pattern pindex   i          i                                          si   sindex   i                      if  si    str len                                                return false                                            char c   toLowerTable str si                        if  c     pattern pindex   i                                                 continue                                            if  si    str len                                                return false                                            if   pattern pindex   i          amp  amp  c                                                       continue                                            breakLoops   true                      break                                    if  breakLoops                                        if   star                                                return false                                            sindex                        if  si    str len                                                return false                                                          else                                       if  start    -1                                                start   sindex                                            if  pindex   i  lt  pattern len  amp  amp   pattern pindex   i                                                        break                                            if  sindex   i    str len                                                if  end  lt   start                                                        end   str len                                                    return true                                            if  i    0  amp  amp   pattern pindex   i - 1                                                        return true                                            if   star                                                return false                                            sindex                        continue                                              sindex    i              pindex    i              if  start    -1                                start   sindex

User · Answer

Often  wild cards operate with two type of jokers       - any character   one and only one      - any characters  zero or more    so you can easily convert these rules into appropriate regular expression        If you want to implement both     and       private static String WildCardToRegular String value        return       Regex Escape value  Replace             Replace                                If you want to implement     only   private static String WildCardToRegular String value        return       Regex Escape value  Replace                            And then you can use Regex as usual      String test    Some Data X      Boolean endsWithEx   Regex IsMatch test  WildCardToRegular   X       Boolean startsWithS   Regex IsMatch test  WildCardToRegular  S        Boolean containsD   Regex IsMatch test  WildCardToRegular   D            Starts with S  ends with X  contains  me  and  a   in that order     Boolean complex   Regex IsMatch test  WildCardToRegular  S me a X

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C  Console application sample     Command line Sample    C    App Exe -Opy PythonFile py 1 2 3   Console output    Argument list  -Opy PythonFile py 1 2 3   Found python filename  PythonFile py     using System  using System Text RegularExpressions              Regex  namespace ConsoleApp1       class Program               static void Main string   args                        string cmdLine   String Join      args                bool bFileExtFlag   false              int argIndex   0              Regex regex              foreach  string s in args                                  Search for the 1st occurrence of the    py  pattern                 regex   new Regex     s     056py   RegexOptions IgnoreCase                   bFileExtFlag   regex IsMatch s                   if  bFileExtFlag    true                      break                  argIndex                                Console WriteLine  Argument list      cmdLine               if  bFileExtFlag    true                  Console WriteLine  Found python filename      args argIndex                else                 Console WriteLine  Python file with extension  lt  py gt  not found

User · Answer

It is necessary to take into consideration  that Regex IsMatch gives true with XYZ  when checking match with Y   To avoid it  I use     anchor  isMatch str1        str2 Replace                   So  full code to solve your problem is      bool isMatchStr string str1  string str2                string s1   str1 Replace                      string s2   str2 Replace                      bool r1   Regex IsMatch s1        s2           bool r2   Regex IsMatch s2        s1           return r1    r2

User · Answer

Just FYI  you could use the VB NET Like-Operator   string text    x is not the same as X and yz not the same as YZ   bool contains   LikeOperator LikeString text   X YZ    Microsoft VisualBasic CompareMethod Binary       Use CompareMethod Text if you want to ignore the case   You need to add using Microsoft VisualBasic CompilerServices

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