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

/
/

Test String

Code Generator

Generated Code

// include the latest version of the regex crate in your Cargo.toml extern crate regex; use regex::Regex; fn main() { let regex = Regex::new(r"^").unwrap(); let string = "class FinUrad { public string Kod { get; set; } public string Nazev { get; set; } public override string ToString() { return Nazev; } } <Grid Margin=\"20\"> <Grid.RowDefinitions> <RowDefinition Height=\"Auto\"/> <RowDefinition Height=\"*\"/> <RowDefinition Height=\"Auto\"/> </Grid.RowDefinitions> <StackPanel Grid.Row=\"0\" Margin=\"0,0,0,10\"> <TextBlock Text=\"Jméno:\"/> <TextBox x:Name=\"txtJmeno\" Margin=\"0,5,0,10\"/> <TextBlock Text=\"Rodné číslo (XXXXXX/XXXX):\"/> <TextBox x:Name=\"txtRC\" Margin=\"0,5,0,10\"/> <TextBlock Text=\"Finanční úřad:\"/> <ComboBox x:Name=\"comboFinUrady\" DisplayMemberPath=\"Nazev\" Margin=\"0,5,0,10\"/> <TextBlock Text=\"Zpráva:\"/> <TextBox x:Name=\"txtZprava\" AcceptsReturn=\"True\" Height=\"80\" Margin=\"0,5,0,10\"/> </StackPanel> <StackPanel Grid.Row=\"2\" Orientation=\"Horizontal\" HorizontalAlignment=\"Right\"> <Button x:Name=\"btnZobrazitHistorii\" Content=\"Zobrazit historii\" Click=\"btnZobrazitHistorii_Click\"/> <Button x:Name=\"btnOdeslat\" Content=\"Odeslat\" Click=\"btnOdeslat_Click\"/> </StackPanel> </Grid> public partial class MainWindow : Window { private ObservableCollection<FinUrad> urady = new(); private const string ApiUrl = \"https://csharp.janjanousek.cz/api/financni-urady/\"; private const string ApiKey = \"VSB\"; public MainWindow() { InitializeComponent(); LoadFinUrady(); } private async void LoadFinUrady() { while (true) { try { using HttpClient client = new(); client.DefaultRequestHeaders.Add(\"x-api-key\", ApiKey); var response = await client.GetAsync(ApiUrl); if (response.StatusCode == System.Net.HttpStatusCode.TooManyRequests) { if (response.Headers.TryGetValues(\"Retry-After\", out var values)) { int secods = int.Parse(values.First()); await Task.Delay(secods * 1000); continue; } } response.EnsureSuccessStatusCode(); var xmlString = await response.Content.ReadAsStringAsync(); var xml = XDocument.Parse(xmlString); var polozky = xml.Descendants(\"POLOZKA\"); foreach (var elem in polozky) { string id = elem.Element(\"CHODNOTA\")?.Value; string name = elem.Element(\"ZKRTEXT\")?.Value; if (!string.IsNullOrEmpty(id) && !string.IsNullOrEmpty(name)) { urady.Add(new FinUrad { Kod = id, Nazev = name }); } } comboFinUrady.ItemsSource = urady; comboFinUrady.SelectedIndex = 0; break; } catch (Exception ex) { MessageBox.Show(\"Chyba pri nacitani financnich uradu: \" + ex.Message); break; } } } private void btnOdeslat_Click(object sender, RoutedEventArgs e) { string jmeno = txtJmeno.Text; string rc = txtRC.Text; var urad = comboFinUrady.SelectedItem as FinUrad; string zprava = txtZprava.Text; if(string.IsNullOrEmpty(jmeno) || string.IsNullOrEmpty(rc) || urad == null || string.IsNullOrEmpty(zprava) || zprava.Length < 10) { MessageBox.Show(\"Všechna pole musí být vyplněna a zpráva musí mít alespoň 10 znaků.\"); return; } if(!System.Text.RegularExpressions.Regex.IsMatch(rc, @\"^\\d{6}/\\d{4}$\")) { MessageBox.Show(\"Rodné číslo musí mít formát 123456/1234.\"); return; } SaveToDatabase(jmeno, rc, urad.Kod, urad.Nazev, zprava); new ResultsWindow().Show(); } private void btnZobrazitHistorii_Click(object sender, RoutedEventArgs e) { new ResultsWindow().Show(); } private void SaveToDatabase(string jmeno, string rc, string idUrad, string nazevUrad, string zprava) { string dbPath = \"formulare.db\"; if(!File.Exists(dbPath)) { using var connection = new SqliteConnection($\"Data Source={dbPath}\"); connection.Open(); var cmd = connection.CreateCommand(); cmd.CommandText = @\" CREATE TABLE IF NOT EXISTS Formulare ( Id INTEGER PRIMARY KEY AUTOINCREMENT, Jmeno TEXT NOT NULL, RodneCislo TEXT NOT NULL, IdUrad TEXT NOT NULL, NazevUrad TEXT NOT NULL, Zprava TEXT NOT NULL )\"; cmd.ExecuteNonQuery(); } using var conn = new SqliteConnection($\"Data Source={dbPath}\"); conn.Open(); var insert = conn.CreateCommand(); insert.CommandText = @\" INSERT INTO Formulare (Jmeno, RodneCislo, IdUrad, NazevUrad, Zprava) VALUES ($jmeno, $rc, $idUrad, $nazevUrad, $zprava)\"; insert.Parameters.AddWithValue(\"$jmeno\", jmeno); insert.Parameters.AddWithValue(\"$rc\", rc); insert.Parameters.AddWithValue(\"$idUrad\", idUrad); insert.Parameters.AddWithValue(\"$nazevUrad\", nazevUrad); insert.Parameters.AddWithValue(\"$zprava\", zprava); insert.ExecuteNonQuery(); } } <Grid> <ListBox x:Name=\"lstHistorie\"/> </Grid> public partial class ResultsWindow : Window { public ResultsWindow() { InitializeComponent(); LoadData(); } private void LoadData() { string dbPath = \"formulare.db\"; if (!File.Exists(dbPath)) return; using var conn = new SqliteConnection($\"Data Source={dbPath}\"); conn.Open(); var cmd = conn.CreateCommand(); cmd.CommandText = @\" SELECT Jmeno, RodneCislo, IdUrad, NazevUrad, Zprava FROM Formulare\"; using var reader = cmd.ExecuteReader(); while (reader.Read()) { lstHistorie.Items.Add($\"Jméno: {reader.GetString(0)}, RČ: {reader.GetString(1)}, Úřad: {reader.GetString(2)}, Zpráva: {reader.GetString(3)}\"); } } }"; // result will be a tuple containing the start and end indices for the first match in the string let result = regex.captures(string); let (start, end) = match result { Some((s, e)) => (s, e), None => { // ... } }; println!("{}", &string[start, end]); }

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 Rust, please visit: https://docs.rs/regex/latest/regex/