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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "^\\s+,?\\[([A-Za-z0-9]+)\\]\\s=\\s([A-Za-z0-9\\@]+),?"; final String string = " [UserLoginName] = @UserLoginName, \n" + " ,[UserExternalId] = @UserExternalId\n" + " ,[UserName] = @UserName\n" + " ,[Password] = @Password\n" + " ,[IsWindowsUser] = @IsWindowsUser\n" + " ,[Active] = @IsActive\n" + " ,[MustChangePassword] = @MustChangePassword\n" + " ,[PasswordExp] = @PasswordExp\n" + " ,[PasswordModifiedDate] = @PasswordModifiedDate\n" + " ,[PasswordPolicyName] = @PasswordPolicyName\n" + " ,[LoginTry] = @LoginTry\n" + " ,[PermissionsRefreshDate] = @PermissionsRefreshDate\n" + " ,[FirstName] = @FirstName\n" + " ,[LastName] = @LastName\n" + " ,[EmailAddress] = @EmailAddress\n" + " ,[DefaultStoreId] = @DefaultStoreId\n" + " ,[EmployeeNumber] = @EmployeeNumber\n" + " ,[Phone] = @Phone\n" + " ,[MobilePhone] = @MobilePhone\n" + " ,[Address1] = @Address1\n" + " ,[Address2] = @Address2\n" + " ,[PostalCode] = @PostalCode\n" + " ,[PostalAddress] = @PostalAddress\n" + " ,[Title] = @Title\n" + " ,[Language] = @Language\n" + " ,[BirthDate] = @BirthDate\n" + " ,[EmploymentDate] = @EmploymentDate\n" + " ,[ResignationDate] = @ResignationDate\n" + " ,[BankaccountNo] = @BankaccountNo\n" + " ,[SocialSecurityNo] = @SocialSecurityNo\n" + " ,[Comment] = @Comment\n" + " ,[Country] = @Country\n" + " ,[vudGUID] = @VudGUID\n" + " ,[CreatedByUserId] = @CreatedByUserId\n" + " ,[ModifiedByUserId] = @ModifiedByUserId\n" + " ,[CreatedDate] = @CreatedDate\n" + " ,[ModifiedDate] = @ModifiedDate\n" + " ,[UseSingleSignOn] = @UseSingleSignOn\n" + " ,[Salt] = @Salt\n" + " ,[IsSystemUser] = @IsSystemUser"; final String subst = "[\\1] = ISNULL(\\2, [\\1]),"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html