Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression

/
/
gms

Test String

Code Generator

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?<text>N?'((?:''|[^'])*)'|N?""((?:""|[^""])*)"")"; string input = @"USE [master] GO IF OBJECT_ID('dbo.sp_foreach_db') IS NOT NULL DROP PROCEDURE [dbo].[sp_foreach_db] GO CREATE PROCEDURE [dbo].[sp_foreach_db] ( @tsql NVARCHAR(MAX) = NULL ,@replacedatabasenamepattern NVARCHAR(20) = N'?' ,@break_on_error BIT = 1 ,@db_name_like NVARCHAR(128) = NULL ,@db_name_in NVARCHAR(4000) = NULL ,@db_name_not_in NVARCHAR(4000) = NULL ,@db_use_system_db BIT = 0 ,@db_use_temp_db BIT = 0 ,@push_info_msg BIT = 1 ) WITH EXECUTE AS CALLER AS /* Version: 1.0.1.0 Developer: Paw Jershauge Created: 18-03-2016 13:01:00 */ BEGIN IF @tsql IS NULL RETURN 0; SET NOCOUNT ON; DECLARE @dbtsql NVARCHAR(MAX) ,@firecode NVARCHAR(MAX) ,@db_name NVARCHAR(128) ,@dbnames NVARCHAR(MAX) = N'' ,@has_replacement BIT = 0 ,@msg_str NVARCHAR(2044) SET @dbtsql = N'SELECT @dbnames += [name] + CHAR(10) FROM [master].[sys].[databases] WHERE [state] = 0' SET @dbtsql += IIF(ISNULL(@db_use_temp_db, 0) = 1, N'', N' AND [database_id] <> 2') SET @dbtsql += IIF(ISNULL(@db_use_system_db, 0) = 1, N'', N' AND [database_id] > 4') SET @dbtsql += IIF(NULLIF(@db_name_like, N'') IS NULL, N'', N' AND [name] LIKE ''' + @db_name_like + N'''') SET @dbtsql += IIF(NULLIF(@db_name_in, N'') IS NULL, N'', N' AND [name] IN (' + @db_name_in + N')') SET @dbtsql += IIF(NULLIF(@db_name_not_in, N'') IS NULL, N'', N' AND [name] NOT IN (' + @db_name_not_in + N')') EXEC sp_executesql @dbtsql, N'@dbnames NVARCHAR(MAX) OUTPUT', @dbnames = @dbnames OUTPUT; SELECT @has_replacement = CAST(CHARINDEX(ISNULL(@replacedatabasenamepattern, N'?'), @tsql) AS BIT) DECLARE cur_db CURSOR LOCAL FORWARD_ONLY FAST_FORWARD READ_ONLY FOR SELECT [value] FROM STRING_SPLIT(@dbnames, CHAR(10)) WHERE [value] <> N'' ORDER BY [value] OPEN cur_db FETCH NEXT FROM cur_db INTO @db_name WHILE @@FETCH_STATUS = 0 BEGIN BEGIN TRY SELECT @firecode = N'EXEC (N''' + IIF(@has_replacement = 0,N'Use [' + @db_name + N']; ', N'') + REPLACE(REPLACE(@tsql, ISNULL(@replacedatabasenamepattern, N'?'), @db_name), N'''', N'''''') + N''')' IF @push_info_msg = 1 BEGIN SET @msg_str = CONVERT(NVARCHAR(40),GETDATE(), 121) + N':Executing on ' + @db_name RAISERROR (@msg_str, 0, 1) WITH NOWAIT END EXEC sp_executesql @firecode IF @push_info_msg = 1 BEGIN SET @msg_str = CONVERT(NVARCHAR(40),GETDATE(), 121) + N':' + @db_name + N' Done!' RAISERROR (@msg_str, 0, 1) WITH NOWAIT END END TRY BEGIN CATCH SET @msg_str = 'Database ' + @db_name + ' failed with the following message:' RAISERROR (@msg_str, 0, 1) WITH NOWAIT SET @msg_str = ERROR_MESSAGE() RAISERROR (@msg_str, 0, 1) WITH NOWAIT --Workaround of the PRINT Command that is stacked and released in reverse order, on remote servers IF @break_on_error = 1 THROW END CATCH FETCH NEXT FROM cur_db INTO @db_name END CLOSE cur_db DEALLOCATE cur_db END GO EXEC sys.sp_MS_marksystemobject sp_foreach_db GO"; RegexOptions options = RegexOptions.Multiline | RegexOptions.Singleline; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx