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
Processing...

Test String

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 = "\\b(class|struct)\\s+([A-Za-z_]\\w*)\\s*(:?\\s*(public|private|protected)?\\s+([A-Za-z_]+))?\\s*\\{(?Us:.*)\\}\\s*;"; final String string = ".*(class|struct)\\s+([^{]+)\\s*[:]?([^{]+){\n" + "\\b(class|struct)\\s+[A-Za-z_]\\s*\\{\n" + "#ifndef STUDENTMODEL_H\n" + "#define STUDENTMODEL_H\n\n" + "#include <QAbstractTableModel>v\n" + "#include <QList>\n\n" + "class\n" + "S : private _jgkdfjgkdlf {};\n\n" + "struct Student {\n" + "public:\n" + " int id;\n" + " QString fio;\n" + " QString group;\n" + " QString shifr;\n" + " double average;\n" + "};\n\n" + "class StudentModel \n" + ": public QAbstractTableModel\n" + "{\n" + " Q_OBJECT\n\n" + "public:\n" + " explicit StudentModel(QObject* parent = nullptr);\n\n" + " Qt::ItemFlags flags(const QModelIndex& index) const override;\n\n" + " // basic functionality\n" + " int rowCount(const QModelIndex& parent = QModelIndex()) const override;\n" + " int columnCount(const QModelIndex& parent = QModelIndex()) const override;\n\n" + " QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;\n" + " QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;\n\n" + " // editable model\n" + " bool setData(const QModelIndex& index, const QVariant& value, int role = Qt::EditRole) override;\n\n" + " bool insertRows(int position, int rows, const QModelIndex& parent = QModelIndex()) override;\n" + " bool removeRows(int position, int rows, const QModelIndex& parent = QModelIndex()) override;\n\n" + " void resetData(const QList<Student>& newData);\n" + " void readFile(const QString& path);\n" + " void writeFile(const QString& path);\n\n" + "private:\n" + " QList<Student> _studentData;\n" + "};\n\n" + "#endif // STUDENTMODEL_H\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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