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

/
/
img

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"^([A-Za-z0-9]\s?)+\s-\s(Before|After)\s((Insert|Update|Delete)|(Insert\/Update))\s-\s([A-Za-z0-9]\s?)+$" test_str = ("Valid Cases matching standards:\n\n" "Opportunity - Before Insert/Update - Update Amount Before We Die\n" "Case - After Update - Send Notification\n" "Lead - Before Delete - Archive Record\n" "Opportunity Line Item - After Insert - 123 sdsad asdasd\n" "Quote Line Asset - Before Insert - Hello World \n" "Account - After Update - Yes Man This Can Be Anything\n\n\n" "Invalid cases:\n" "account - Before Save - Update Name (Object should start with an uppercase letter)\n" "Account - before save - Update Name (Context should start with an uppercase letter)\n" "Account - Before Save - update name (Action should start with an uppercase letter)\n" "Account-Before Save-Update Name (Missing spaces around hyphens)\n" "Account - Before/After Save - Update Name (Invalid characters in Context)\n" "Custom_Object__c - After Undelete - Restore Record\n" "Opportunity_Line_Item - Before Insert - Validate Quantity") matches = re.finditer(regex, test_str, re.IGNORECASE | 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