Regular Expressions 101

Save & Manage Regex

  • Current Version: 1
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
There are currently no sponsors. Become a sponsor today!
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

Language

Generated Code

import Foundation let pattern = #"(Fatal data error processing file '[^\']+'\.\n?\s?|General failure \(\d+\): )(?<Exception>[^\n\$]+)"# let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines) let testString = #""" FILE_READER[1]: TT19472 Fatal data error processing file '/default/folder/ingest/amr_ca_sf_items_658721_US.out'. Field length overflow(s) in record 2355, field 17, 'COUNT_DESC'. Expected 300 bytes, field contained 307 bytes. FILE_READER[1]: TT19015 TPT Exit code set to 12. $FILE_READER: DataConnector Producer operator Instances: 1 $FILE_READER: ECI operator ID: '$FILE_READER-18808' $FILE_READER: Operator instance 1 processing file '/default/folder/ingest/amr_ca_sf_items_658721_US.out'. $FILE_READER: TT19472 Fatal data error processing file '/default/folder/ingest/amr_ca_sf_items_658721_US.out'. Field length overflow(s) in record 1, field 1, '"ORDER"'. Expected 20 bytes, field contained 841 bytes. $FILE_READER: TT19015 TPT Exit code set to 12. FILE_READER: TT19434 pmAttach failed. General failure (34): '!ERROR! dlopen failed: /default/folder/installations/lib/axm.so: cannot open shared object file: No such file or directory' FILE_READER: TT19302 Fatal error loading access module. FILE_READER: TT19015 TPT Exit code set to 12. FILE_READER: TT19134 !ERROR! Fatal data error processing file '/default/folder/ingest/rpv0410_12123_1.out.gz'. Delimited Data Parsing error: Too many columns in row 246. FILE_READER: TT19015 TPT Exit code set to 12. FILE_WRITER: TT19434 pmWrite failed. General failure (34): 'pmunxWBuf: fwrite byte count error (No space left on device)' FILE_WRITER: TT19306 Fatal error writing data. FILE_WRITER: TT19015 TPT Exit code set to 12. """# let stringRange = NSRange(location: 0, length: testString.utf16.count) let matches = regex.matches(in: testString, range: stringRange) var result: [[String]] = [] for match in matches { var groups: [String] = [] for rangeIndex in 1 ..< match.numberOfRanges { let nsRange = match.range(at: rangeIndex) guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue } let string = (testString as NSString).substring(with: nsRange) groups.append(string) } if !groups.isEmpty { result.append(groups) } } print(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 Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression