Need to perform Wildcard etc search on a string using Regex

Question

I need to perform Wildcard        etc   search on a string  This is what I have done   string input    Message   string pattern    d    Regex regex   new Regex pattern  RegexOptions IgnoreCase    if  regex IsMatch input         MessageBox Show  Found      else       MessageBox Show  Not Found        With the above code  Found  block is hitting but actually it should not   If my pattern is  e   then only  Found  should hit   My understanding or requirement is d  search should find the text containing  d  followed by any characters   Should I change my pattern as  d    and  e     Is there any support in  NET for Wild Card which internally does it while using Regex class

User · Answer

d  means that it should match zero or more  d  characters  So any string is a valid match  Try d  instead   In order to have support for wildcard patterns I would replace the wildcards with the RegEx equivalents  Like   becomes    and   becomes     Then your expression above becomes d

User · Answer

All upper code is not correct to the end   This is because when searching zz foo  or zz  you will not get correct results   And if you search  abcd   in  abcd  in TotalCommander will he find a abcd file so all upper code is wrong   Here is the correct code   public string WildcardToRegex string pattern                     string result  Regex Escape pattern           Replace                        Replace                    if  result EndsWith                       result   result Remove result Length - 3  3           result                     return result

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You need to convert your wildcard expression to a regular expression  For example       private bool WildcardMatch String s  String wildcard  bool case sensitive                   Replace the   with an    and the   with a dot  Put   at the            beginning and a   at the end         String pattern         Regex Escape wildcard  Replace              Replace                                Now  run the Regex as you already know         Regex regex          if case sensitive              regex   new Regex pattern           else             regex   new Regex pattern  RegexOptions IgnoreCase            return regex IsMatch s

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You must escape special Regex symbols in input wildcard pattern  for example pattern   txt will equivalent to      txt   So slashes  braces and many special symbols must be replaced with        s  where s - special Regex symbol

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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                                   Use  var ismatch2   Wildcard Match  quot xmlfsdfsd quot    quot xml  quot

User · Answer

You can do a simple wildcard mach without RegEx using a Visual Basic function called LikeString   using Microsoft VisualBasic  using Microsoft VisualBasic CompilerServices   if  Operators LikeString  This is just a test     just    CompareMethod Text       Console WriteLine  This matched         If you use CompareMethod Text it will compare case-insensitive  For case-sensitive comparison  you can use CompareMethod Binary   More info here  http   www henrikbrinch dk Blog 2012 02 14 Wildcard-matching-in-C  MSDN  http   msdn microsoft com en-us library microsoft visualbasic compilerservices operators likestring 28v vs 100 29 ASPX

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Windows and  nux treat wildcards differently       and   are processed in a very complex way by Windows  one s presence or position would change another s meaning  While  nux keeps it simple  all it does is just one simple pattern match  Besides that  Windows matches   for 0 or 1 chars  Linux matches it for exactly 1 chars   I didn t find authoritative documents on this matter  here is just my conclusion based on days of tests on Windows 8 XP  command line  dir command to be specific  and the Directory GetFiles method uses the same rules too  and Ubuntu Server 12 04 1  ls command   I made tens of common and uncommon cases work  although there are many failed cases too   The current answer by Gabe  works like  nux  If you also want a Windows style one  and are willing to accept the imperfection  then here it is            lt summary gt           lt para gt Tests if a file name matches the given wildcard pattern  uses the same rule as shell commands  lt  para gt           lt  summary gt           lt param name  fileName  gt The file name to test  without folder  lt  param gt           lt param name  pattern  gt A wildcard pattern which can use char   to match any amount of characters  or char   to match one character  lt  param gt           lt param name  unixStyle  gt If true  use the  nix style wildcard rules  otherwise use windows style rules  lt  param gt           lt returns gt true if the file name matches the pattern  false otherwise  lt  returns gt      public static bool MatchesWildcard this string fileName  string pattern  bool unixStyle                if  fileName    null              throw new ArgumentNullException  fileName             if  pattern    null              throw new ArgumentNullException  pattern             if  unixStyle              return WildcardMatchesUnixStyle pattern  fileName            return WildcardMatchesWindowsStyle fileName  pattern              private static bool WildcardMatchesWindowsStyle string fileName  string pattern                var dotdot   pattern IndexOf       StringComparison Ordinal           if  dotdot  gt   0                        for  var i   dotdot  i  lt  pattern Length  i                    if  pattern i                              return false                     var normalized   Regex Replace pattern                        var endsWithDot   normalized Length    pattern Length           var endWeight   0          if  endsWithDot                        var lastNonWildcard   normalized Length - 1              for    lastNonWildcard  gt   0  lastNonWildcard--                                var c   normalized lastNonWildcard                   if  c                             endWeight    short MaxValue                  else if  c                             endWeight    1                  else                     break                             if  endWeight  gt  0                  normalized   normalized Substring 0  lastNonWildcard   1                      var endsWithWildcardDot   endWeight  gt  0          var endsWithDotWildcardDot   endsWithWildcardDot  amp  amp  normalized EndsWith               if  endsWithDotWildcardDot              normalized   normalized Substring 0  normalized Length - 1            normalized   Regex Replace normalized                                     var escaped   Regex Escape normalized           string head  tail           if  endsWithDotWildcardDot                        head         escaped              tail             0     endWeight                             else if  endsWithWildcardDot                        head         escaped              tail         0     endWeight                           else                       head         escaped              tail                           if  head EndsWith           amp  amp  head Length  gt  5                        head   head Substring 0  head Length - 4               tail                tail                     var regex   head Replace              Replace                   tail          return Regex IsMatch fileName  regex  RegexOptions IgnoreCase              private static bool WildcardMatchesUnixStyle string pattern  string text                var regex         Regex Escape pattern                                  Replace                                              Replace                                                 return Regex IsMatch text  regex           There s a funny thing  even the Windows API PathMatchSpec does not agree with FindFirstFile  Just try a1    FindFirstFile says it matches a1  PathMatchSpec says not

User · Answer

You may want to use WildcardPattern from System Management Automation assembly  See my answer here

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From http   www codeproject com KB recipes wildcardtoregex aspx   public static string WildcardToRegex string pattern        return       Regex Escape pattern                         Replace                                     Replace                                       So something like foo  xls  will get transformed to  foo    xls

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I think  Dmitri has nice solution at  Matching strings with wildcard https   stackoverflow com a 30300521 1726296  Based on his solution  I have created two extension methods   credit goes to him   May be helpful   public static String WildCardToRegular this String value            return       Regex Escape value  Replace             Replace                        public static bool WildCardMatch this String value string pattern bool ignoreCase   true            if  ignoreCase              return Regex IsMatch value  WildCardToRegular pattern   RegexOptions IgnoreCase            return Regex IsMatch value  WildCardToRegular pattern        Usage   string pattern    file      var isMatched    file doc  WildCardMatch pattern    or  string xlsxFile    file xlsx  var isMatched   xlsxFile WildCardMatch pattern

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The correct regular expression formulation of the glob expression d  is  d  which means match anything that starts with d       string input    Message       string pattern      d       Regex regex   new Regex pattern  RegexOptions IgnoreCase      The   quoting is not necessary in this case  but good practice since many regexes use backslash escapes that need to be left alone  and it also indicates to the reader that this string is special

[c#] Need to perform Wildcard (*,?, etc) search on a string using Regex

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