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

/
/
gm

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "^(?i)CHOC.*[.csv]$"; final String string = "CHOC_METRICS_2020-06-16.csv\n" + "Claims_PGSEO_20200110.txt\n" + "Claims_Agilon_20200110.txt\n" + "COPC_PE20190701_REHCF.TXT\n" + "Member_Agilon_PGSEO_Current_QualityRA_History_20200116.txt\n" + "Member_Agilon_PGSEO_Current_QualityRA_20200215.txt\n" + "Member_Agilon_PGSEO_Locked_Financial_20200115.txt\n" + "Member_Agilon_PGSEO_Locked_Financial_History_20200116.txt\n" + "Claims_PGSEO_History_20200116.txt\n" + "Member_Agilon_Current_QualityRA_20200215.txt\n" + "Member_Agilon_Locked_Financial_20191215.txt\n" + "COPC_ME_AETACOE6_201912_20200127.txt\n" + "SGPPN_PE20190701_REHCF.TXT\n" + "SGPPN_PE20200101_RECLMEXP.TXT\n" + "SGAGAKRN_PE20200301_RECLMEXP.TXT\n" + "PCMS_Inpatient_Admission_Patients_20190802100552.csv\n" + "PCMS_Inpatient_Admission_Patients_20190821154559.csv\n" + "Humana Dayton Census - Authorizations 4.30.20 Authorizations.csv\n" + "Humana Dayton Census - Authorizations 5.11.20.csv\n" + "Humana Dayton Census - Authorizations 4.30.20 Admits Discharges.csv\n" + "2020_05_04_Census.txt\n" + "2020_05_03_Discharges_Rolling7Days.txt\n" + "2020_05_04_Census.txt\n" + "2020_05_04_Discharges_Rolling7Days.txt\n" + "2019_12_21_Discharges_Rolling7Days.txt\n" + "2019_12_21_Census.txt\n" + "CHOC_RT_OutreachAttempt_20200502.csv\n" + "CHOC_RT_OutreachAttempt_20200509.csv\n" + "SGPPN_PE20200101_REMBX.TXT\n" + "PriMed_Phy_MAPPO_claim_det_02132020.txt\n" + "PriMed_Phy_MAPPO_claim_header_02132020.txt\n" + "PriMed_Phy_MAPPO_claim_header_proc_02132020.txt\n" + "PriMed_Phy_MAPPO_CLM_DIAG_02132020.txt\n" + "PriMed_Phy_MAPPO_member_02132020.txt\n" + "PriMed_Phy_MAPPO_member_eligibility_02132020.txt\n" + "OHCore_Care_Select_member_eligibility_01232020.txt\n" + "OHCore_Care_Select_member_eligibility_04152019.txt\n" + "OHCore_Care_Select_claim_det_07152019.txt\n" + "OHCore_Care_Select_claim_det_06182018.txt\n" + "OHCore_Care_Select_claim_det_01232020.txt\n" + "Pioneer_Phy_MAPPO_claim_det_02132020.txt\n" + "Pioneer_Phy_MAPPO_claim_header_02132020.txt\n" + "Pioneer_Phy_MAPPO_claim_header_proc_02132020.txt\n" + "Pioneer_Phy_MAPPO_CLM_DIAG_02132020.txt\n" + "Pioneer_Phy_MAPPO_member_02132020.txt\n" + "Pioneer_Phy_MAPPO_member_eligibility_02132020.txt\n" + "Physicians_Grp_Sohio_MAPPO_claim_det_02132020.txt\n" + "Physicians_Grp_Sohio_MAPPO_claim_header_02132020.txt\n" + "Physicians_Grp_Sohio_MAPPO_claim_header_proc_02132020.txt\n" + "Physicians_Grp_Sohio_MAPPO_CLM_DIAG_02132020.txt\n" + "Physicians_Grp_Sohio_MAPPO_member_02132020.txt\n" + "Physicians_Grp_Sohio_MAPPO_member_eligibility_02132020.txt\n" + "Central_Ohio_PC_MAPPO_claim_det_02132020.txt\n" + "Central_Ohio_PC_MAPPO_claim_header_02132020.txt\n" + "Central_Ohio_PC_MAPPO_CLM_DIAG_02132020.txt\n" + "Central_Ohio_PC_MAPPO_member_02132020.txt\n" + "Central_Ohio_PC_MAPPO_member_eligibility_02132020.txt\n" + "Central_Ohio_PC_MAPPO_claim_header_proc_02132020.txt\n" + "CORECARESELECT1OH_ENC_837P_20190927_529128\n" + "Copy of Pioneer_DailyAuth_SummaCare_20191227.csv\n" + "Copy of Pioneer_DailyAuth_SummaCare_20200329.csv\n" + "Copy of Pioneer_DailyAuth_SummaCare_20200414.csv\n" + "Copy of Pioneer_DailyAuth_SummaCare_20200402.csv\n" + "Pioneer_DailyAuth_SummaCare_20191227.csv\n" + "Pioneer_DailyAuth_SummaCare_20200329.csv\n" + "MG 11.22.19 HospitalListReport.csv\n" + "Humana COPC Census - Authorizations 3.26.20 Admits Discharges.csv\n" + "Humana COPC Census - Authorizations 13.6.20 Admits Discharges.csv\n" + "Humana COPC Census - Authorizations 3.26.20 Authorizations.csv\n" + "Humana COPC Census - Authorizations 11.01.20 Authorizations.csv\n" + "Humana COPC Census - Authorizations 2.2.20 Authorizations.csv\n" + "Humana Census - Admits Discharges 20200420.csv\n" + "^0420 file bad\n" + "Humana Census - Admits Discharges 20200416.csv\n" + "Humana Census - Authorizations 20200416.csv"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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