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

/
/
g

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"(public|protected|private|static|\s) +[\w\<\>\[\]]+\s+(\w+) *\([^\)]*\)\s*(\{)" test_str = ("/*\n" " * Licensed to the Apache Software Foundation (ASF) under one or more\n" " * contributor license agreements. See the NOTICE file distributed with\n" " * this work for additional information regarding copyright ownership.\n" " * The ASF licenses this file to You under the Apache License, Version 2.0\n" " * (the \"License\"); you may not use this file except in compliance with\n" " * the License. You may obtain a copy of the License at\n" " *\n" " * http://www.apache.org/licenses/LICENSE-2.0\n" " *\n" " * Unless required by applicable law or agreed to in writing, software\n" " * distributed under the License is distributed on an \"AS IS\" BASIS,\n" " * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n" " * See the License for the specific language governing permissions and\n" " * limitations under the License.\n" " */\n" "package org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline;\n\n" "import org.apache.pdfbox.cos.COSDictionary;\n" "import org.apache.pdfbox.cos.COSName;\n\n" "/**\n" " * This represents an outline in a pdf document.\n" " *\n" " * @author <a href=\"mailto:ben@benlitchfield.com\">Ben Litchfield</a>\n" " * @version $Revision: 1.2 $\n" " */\n" "public final class PDDocumentOutline extends PDOutlineNode\n" "{\n\n" " \n" " static java.io.BufferedWriter bfn;\n" " static java.io.BufferedWriter bf;\n\n" " /**\n" " * Default Constructor.\n" " */\n" " public PDDocumentOutline()\n" " {\n" " \n" " getCOSDictionary().setName(COSName.TYPE, COSName.OUTLINES.getName());\n" " \n" " }\n\n" " /**\n" " * Constructor for an existing document outline.\n" " *\n" " * @param dic The storage dictionary.\n" " */\n" " public PDDocumentOutline( COSDictionary dic )\n" " {\n" " super( dic );\n" " getCOSDictionary().setName(COSName.TYPE, COSName.OUTLINES.getName());\n" " }\n\n" " @Override\n" " public boolean isNodeOpen()\n" " {\n" " return true;\n" " }\n\n" " @Override\n" " public void openNode()\n" " {\n" " // The root of the outline hierarchy is not an OutlineItem and cannot be opened or closed\n" " }\n\n" " @Override\n" " public void closeNode()\n" " {\n" " // The root of the outline hierarchy is not an OutlineItem and cannot be opened or closed\n" " }\n" "}\n") matches = re.finditer(regex, test_str) 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