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 (24)

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

/
/
gm

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"(?<!\d|-|\/|to|\$)(?<!\$(\d)\.)([1-9][0-9]{0,2}(\.\d{0,2})?\s?)(lbs|lb|LBS|LB|KG|kg|G|g|L|l+)(?!\d|\w)" test_str = ("10lb Potato bag\n" "Apples Gld Delicious 3lb\n" "Grandfer Rocha Pear2.5lbs\n" "CHIN.MAND.5LB\n" "Batata Veg (10LB)\n" "SIG 170LB99 Legging SzB 1ea\n" "ARJO CDA1450035 SupBlk 400LB1ea\n" "AHC EB205L \n" "DRI 10220-1 Bariatric500lb 1 ea\n" "TILDA SONA MASOORI 20 LBS\n" "OVAL ROASTER 9 - 12 LBS\n" "ORGANIC TRIPACK FRUIT 1.2 KG\n" "KGF5KT2404 PEPLUM T, PURPLE\n" "AIR 1773LB-XL 15-20 KnXL 1ea\n" "PLUM BAG 1KG US\n" "NEXT XTRA 100G\n" "SUDOCREM 60G\n" "EGGPLANT GRILLED IN OIL (3KG)\n" "CORONATION GRAPE 2L CA\n" "MEAT DEAL $11.00 KG\n" "LIVE LOBSTER- 2.00-3.00 LB-MSC\n" "PC MAGIC GROW 20-20-20 3.55KG\n" "KGF7W3409 KGVELCROWB,GREY\n" "TZATZIKI 500G\n" "2+1 LEAD MIX") matches = re.finditer(regex, test_str, re.MULTILINE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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 Python, please visit: https://docs.python.org/3/library/re.html