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
No Match

@"
"
gm

Test String

Substitution

Processing...

Code Generator

Language

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"(?m)modelBuilder\.Entity<(?'type'\w+)>\(builder =>\n\s*\{(?'builder'[\w\W]+?)\}\);").unwrap(); let string = "modelBuilder.Entity<Foobar>(builder => { builder.HasKey(e => e.Id).HasName(\"PRIMARY\"); builder .ToTable(\"foobar\") .UseCollation(\"utf8mb4_0900_ai_ci\"); builder.HasIndex(e => e.A, \"A\").IsUnique(); builder.Property(e => e.D).HasColumnType(\"datetime\"); builder.Property(e => e.E) .HasMaxLength(255) .UseCollation(\"utf8mb4_unicode_ci\"); builder.Property(e => e.N) .HasMaxLength(255) .UseCollation(\"utf8mb4_unicode_ci\"); builder.HasOne(d => d.ANav).WithOne(p => p.BNav) .HasForeignKey<Foobar>(d => d.Leerling) .HasConstraintName(\"Foobar_fk\"); });"; let substitution = "public class $1Mapping : IEntityTypeConfiguration<$1>\\n{\\n public void Configure(EntityTypeBuilder<$1> builder)\\n {\\n$2\\n}}"; // result will be a String with the substituted value let result = regex.replace_all(string, substitution); println!("{}", 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 Rust, please visit: https://docs.rs/regex/latest/regex/