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

/
/
gx

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?m)^\\s*\\d+\\..*\\R{2} # Get to the title\n" + "(?<title>[^\\n]*(?:\\n(?!\\n)[^\\n]*)*) # Get title\n" + "\\R{2} # Get to the authors\n" + "[^\\n]*(?:\\n(?!\\R)[^\\R]*)* # Consume authors\n" + "(?<abstract>[^\\[]*(?:\\[(?!PubMed[ ]-[ ]indexed[ ]for[ ]MEDLINE\\])[^\\[]*)*) # Grab abstract"; final String string = "1. Br J Biomed Sci. 2015;72(3):93-101.\n\n" + "Effects of propofol and isoflurane on haemodynamics and the inflammatory response\n" + "in cardiopulmonary bypass surgery.\n\n" + "Sayed S, Idriss NK, Sayyedf HG, Ashry AA, Rafatt DM, Mohamed AO, Blann AD.\n\n" + "Cardiopulmonary bypass (CPB) causes reperfusion injury that when most severe is\n" + "clinically manifested as a systemic inflammatory response syndrome. The\n" + "anaesthetic propofol may have anti-inflammatory properties that may reduce such a\n" + "response. We hypothesised differing effects of propofol and isoflurane on\n" + "inflammatory markers in patients having CBR Forty patients undergoing elective\n" + "CPB were randomised to receive either propofol or isoflurane for maintenance of\n" + "anaesthesia. CRP, IL-6, IL-8, HIF-1α (ELISA), CD11 and CD18 expression (flow\n" + "cytometry), and haemoxygenase (HO-1) promoter polymorphisms (PCR/electrophoresis)\n" + "were measured before anaesthetic induction, 4 hours post-CPB, and 24 hours later.\n" + "There were no differences in the 4 hours changes in CRP, IL-6, IL-8 or CD18\n" + "between the two groups, but those in the propofol group had higher HIF-1α (P =\n" + "0.016) and lower CD11 expression (P = 0.026). After 24 hours, compared to the\n" + "isoflurane group, the propofol group had significantly lower levels of CRP (P <\n" + "0.001), IL-6 (P < 0.001) and IL-8 (P < 0.001), with higher levels CD11 (P =\n" + "0.009) and CD18 (P = 0.002) expression. After 24 hours, patients on propofol had \n" + "increased expression of shorter HO-1 GT(n) repeats than patients on isoflurane (P\n" + "= 0.001). Use of propofol in CPB is associated with a less adverse inflammatory\n" + "profile than is isofluorane, and an increased up-regulation of HO-1. This\n" + "supports the hypothesis that propofol has anti-inflammatory activity.\n\n" + "PMID: 26510263 [PubMed - indexed for MEDLINE]\n" + "11. Br J Biomed Sci. 2015;72(3):93-101.\n\n" + "Effects of propofol and isoflurane on haemodynamics and the inflammatory response\n" + "in cardiopulmonary bypass surgery.\n\n" + "Sayed S, Idriss NK, Sayyedf HG, Ashry AA, Rafatt DM, Mohamed AO, Blann AD.\n\n" + "Cardiopulmonary bypass (CPB) causes reperfusion injury that when most severe is\n" + "clinically manifested as a systemic inflammatory response syndrome. The\n" + "anaesthetic propofol may have anti-inflammatory properties that may reduce such a\n" + "response. We hypothesised differing effects of propofol and isoflurane on\n" + "inflammatory markers in patients having CBR Forty patients undergoing elective\n" + "CPB were randomised to receive either propofol or isoflurane for maintenance of\n" + "anaesthesia. CRP, IL-6, IL-8, HIF-1α (ELISA), CD11 and CD18 expression (flow\n" + "cytometry), and haemoxygenase (HO-1) promoter polymorphisms (PCR/electrophoresis)\n" + "were measured before anaesthetic induction, 4 hours post-CPB, and 24 hours later.\n" + "There were no differences in the 4 hours changes in CRP, IL-6, IL-8 or CD18\n" + "between the two groups, but those in the propofol group had higher HIF-1α (P =\n" + "0.016) and lower CD11 expression (P = 0.026). After 24 hours, compared to the\n" + "isoflurane group, the propofol group had significantly lower levels of CRP (P <\n" + "0.001), IL-6 (P < 0.001) and IL-8 (P < 0.001), with higher levels CD11 (P =\n" + "0.009) and CD18 (P = 0.002) expression. After 24 hours, patients on propofol had \n" + "increased expression of shorter HO-1 GT(n) repeats than patients on isoflurane (P\n" + "= 0.001). Use of propofol in CPB is associated with a less adverse inflammatory\n" + "profile than is isofluorane, and an increased up-regulation of HO-1. This\n" + "supports the hypothesis that propofol has anti-inflammatory activity.\n\n" + "PMID: 26510263 [PubMed - indexed for MEDLINE]"; final Pattern pattern = Pattern.compile(regex, Pattern.COMMENTS); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html