Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

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
No Match

/
/

Test String

Code Generator

Language

Generated Code

const regex = /(?s)Rx Power[\s\t]+\(mW\)\|[\s\t]+(.*?)[\s\t]+\|.*?\|.*?\|[\s\t]+HIGH[\s\t]+(.*?)[\s\t]+\|[\s\t]+(.*?)[\s\t]+\|.*?\|.*?\|.*?\|.*?\|.*?\|[\s\t]+LOW[\s\t]+(.*?)[\s\t]+\|[\s\t]+(-?\d+)[\s\t]+\|/; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?s)Rx Power[\\s\\t]+\\(mW\\)\\|[\\s\\t]+(.*?)[\\s\\t]+\\|.*?\\|.*?\\|[\\s\\t]+HIGH[\\s\\t]+(.*?)[\\s\\t]+\\|[\\s\\t]+(.*?)[\\s\\t]+\\|.*?\\|.*?\\|.*?\\|.*?\\|.*?\\|[\\s\\t]+LOW[\\s\\t]+(.*?)[\\s\\t]+\\|[\\s\\t]+(-?\\d+)[\\s\\t]+\\|', '') const str = `+--------------------- XCVR DIAGNOSTICS - Port 9 -----------------+ | | | Alarm | Warning | | Output | Value | Threshold | Flag | Threshold | Flag | +---------------+----------+---------------+------+---------------+------+ +---------------+----------+---------------+------+---------------+------+ | Temp (degC)| 27.961 | HIGH 83.000 | 0 | HIGH 80.000 | 0 | | | | LOW -13.000 | 0 | LOW -10.000 | 0 | +---------------+----------+---------------+------+---------------+------+ | Tx Bias (mA)| 35.002 | HIGH 80.000 | 0 | HIGH 75.000 | 0 | | | | LOW 15.000 | 0 | LOW 20.000 | 0 | +---------------+----------+---------------+------+---------------+------+ | Tx Power (mW)| 0.59930 | HIGH 1.41250 | 0 | HIGH 1.25890 | 0 | | | | LOW 0.19950 | 0 | LOW 0.25120 | 0 | +---------------+----------+---------------+------+---------------+------+ | Tx Power (dBm)| -2.2236 | HIGH +1.4999 | 0 | HIGH +0.9999 | 0 | | | | LOW -7.0006 | 0 | LOW -5.9998 | 0 | +---------------+----------+---------------+------+---------------+------+ | Rx Power (mW)| 0.57770 | HIGH 1.77830 | 0 | HIGH 1.58490 | 0 | | | | LOW 0.01000 | 0 | LOW 0.01580 | 0 | +---------------+----------+---------------+------+---------------+------+ | Rx Power (dBm)| -2.3830 | HIGH +2.5001 | 0 | HIGH +2.0000 | 0 | | | | LOW -20.0000 | 0 | LOW -18.0134 | 0 | +---------------+----------+---------------+------+---------------+------+ | Aux1 | 3.32770 | HIGH 3.63000 | 0 | HIGH 3.50000 | 0 | | | | LOW 3.00000 | 0 | LOW 3.10000 | 0 | +---------------+----------+---------------+------+---------------+------+ | Aux2 | 0.00000 | HIGH 5.50000 | 0 | HIGH 5.30000 | 0 | | | | LOW 4.50000 | 0 | LOW 4.70000 | 0 | +---------------+----------+---------------+------+---------------+------+ | 1.8V | | HIGH | 0 | HIGH | 0 | | | | LOW | 0 | LOW | 0 | +---------------+----------+---------------+------+---------------+------+ | -5.2V | | HIGH | 0 | HIGH | 0 | | | | LOW | 0 | LOW | 0 | +---------------+----------+---------------+------+---------------+------+ | Fault/Status Flags | +--------+-------+--------+--------+--------+--------+--------+----------+ | TX_NR | TX | TX_CDR | RX_NR | | RX_CDR | | Reset | | Status | Fault | Unlock | Status | RX_LOS | Unlock | MOD_NR | Complete | +--------+-------+--------+--------+--------+--------+--------+----------+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | +--------+-------+--------+--------+--------+--------+--------+----------+ |APD Sply| TEC | Wavelength | Bad Ch | New Ch | UnSupp | | | Fault | Fault | Unlocked | Req | Acq | TxDith | | +--------+-------+-----------------+--------+--------+--------+----------+ | 0 | 0 | 0 | 0 | 0 | 0 | | +--------+-------+-----------------+--------+--------+--------+----------+ | General Control/Status Signals | +---------+---------+--------+--------+--------+-------+-----+-----------+ | TX | Soft TX | | P_Down | Soft | | RX | Data_Not | | Disable | Disable | MOD_NR | State | P_Down | INTRn | LOS | _Ready | +---------+---------+--------+--------+--------+-------+-----+-----------+ | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | +---------+---------+--------+--------+--------+-------+-----+-----------+ | TX_NR | TX | TX_CDR | RX_NR | RX_CDR | Tx | Tx | | | State | Fault | Unlock | State | Unlock | Tune | Dith | | +---------+---------+--------+--------+--------+-------+-----+-----------+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | +---------+---------+--------+--------+--------+-------+-----+-----------+ | Module Capabilites | +-------------------------+-----------------------+----------------------+ | Laser First Freq (GHz) | Laser Last Freq (GHz) | Grid Spacing (GHz) | +-------------------------+-----------------------+----------------------+ | 0 | 0 | 0 | +-------------------------+-----------------------+----------------------+ | Frequency Channel Control | +---------------------------------+--------------------------------------+ | Channel Number Set | Frequency Error (GHz) | +---------------------------------+--------------------------------------+ | 0 | 0 | +---------------------------------+--------------------------------------+`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; if ((m = regex.exec(str)) !== null) { // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions