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

r"
"
gx

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 = "# Parse table of SWPC event data\n" + "(?P<event>\\d{4})\n" + "\\s+\n" + "(?P<multi_event_flag>\\+)?\n" + "\\s+\n" + "(?P<time_start_flag>\\w)?\n" + "(?P<time_start>\\d{4})\n" + "\\s+\n" + "(?P<time_peak_flag>\\w)?\n" + "(?:\n" + " (?P<time_peak>\\d{4})|\n" + " /{4}\n" + ")\n" + "\\s+\n" + "(?P<time_end_flag>\\w)?\n" + "(?P<time_end>\\d{4})\n" + "\\s+\n" + "(?P<observatory>\\w{3})\n" + "\\s+\n" + "(?P<quality>\\w)\n" + "\\s+\n" + "(?P<type>\\w{3})\n" + "\\s+\n" + "(?:\n" + " (?P<location>\n" + " (?P<lat_hg>\\w\\d{2})\n" + " (?P<long_hg>\\w\\d{2})\n" + " )|\n" + " (?P<frequency_range>\n" + " (?P<from>\\w+)\n" + " \\-\n" + " (?P<to>\\w+)\n" + " )|\n" + " (?P<frequency>\n" + " (\\d{3})\n" + " )|\n" + " (?P<no_freq>\n" + " (/{4})\n" + " )\n" + ")\n" + "\\s+\n" + "(?P<particulars_1>[\\w/\\.\\+]+)\n" + "\\s+\n" + "(?:\n" + " (?P<particulars_2>\n" + " (?:\\d\\.\\d\\w[\\-\\+]\\d{2})?\n" + " )|\n" + " (?P<particulars_3>\\w{3}?)|\n" + " ()\n" + ")\n" + "\\s+\n" + "(?:\n" + " (?P<regnum>\\d{4})|\n" + " ()\n" + ")\n" + "\\n"; final String string = ":Product: 20050316events.txt\n" + ":Created: 2005 Mar 17 1802 UT\n" + ":Date: 2005 03 16\n" + "# Prepared by the U.S. Dept. of Commerce, NOAA, Space Environment Center.\n" + "# Please send comments and suggestions to SEC.Webmaster@noaa.gov \n" + "#\n" + "# Missing data: ////\n" + "# Updated every 30 minutes.\n" + "# Edited Events for 2005 Mar 16\n" + "#\n" + "#Event Begin Max End Obs Q Type Loc/Frq Particulars Reg#\n" + "#-------------------------------------------------------------------------------\n\n" + "1590 0318 0318 0318 LEA G RBR 245 51 \n\n" + "1620 + 0348 //// 1635 COM C RSP 30-80 CTM/1 \n\n" + "1600 + 0408 0410 0412 LEA G RBR 245 210 \n\n" + "1730 + 0422 1214 1511 COM G RNS 245 160 \n\n" + "1610 0522 0528 0532 G10 5 XRA 1-8A B4.2 1.9E-04 \n\n" + "1630 0741 0744 0748 G10 5 XRA 1-8A B1.9 7.3E-05 \n" + "1630 0741 //// 0743 SVI C RSP 025-089 III/1 \n\n" + "1640 1052 //// 1053 SVI U RSP 025-046 III/1 \n\n" + "1650 1125 1125 1125 SVI G RBR 245 85 \n" + "1650 1125 1125 1125 SVI G RBR 410 46 \n\n" + "1660 1150 //// 1150 SVI C RSP 025-041 III/1 \n\n" + "1670 + 1205 1208 1210 G12 5 XRA 1-8A B3.5 8.1E-05 0742\n" + "1670 1206 1206 1209 SAG G RBR 245 100 0742\n" + "1670 1207 1207 1207 SAG G RBR 410 56 0742\n" + "1670 1209 1210 1210 G12 5 XFL S02W48 3.0E+02 6.5E+02 0742\n" + "1670 1210 //// 2228 SAG C RSP 110-180 CTM/1 0742\n\n" + "1680 + 1217 1221 1223 G12 5 XRA 1-8A B5.1 1.4E-04 0742\n" + "1680 + 1219 1219 1219 SVI G RBR 410 310 0742\n" + "1680 1221 1222 1223 G12 5 XFL S03W50 7.5E+02 2.3E+03 0742\n\n" + "1690 + 1242 1245 1247 G12 5 XRA 1-8A B3.1 7.7E-05 0742\n" + "1690 1246 1246 1247 G12 5 XFL S07W48 4.3E+02 9.1E+02 0742\n\n" + "1700 + 1306 //// 1306 SAG C RSP 030-053 III/1 \n\n" + "1710 + 1318 1322 1332 G12 5 XRA 1-8A B3.0 2.3E-04 0742\n" + "1710 1322 1327 1331 G12 5 XFL S07W53 2.3E+02 4.6E+02 0742\n\n" + "1720 + 1339 //// 1339 SVI C RSP 025-034 III/1 \n\n" + "1750 1450 //// 1451 SVI C RSP 025-180 III/1 \n\n" + "1760 + 1542 1547 1554 G12 5 XRA 1-8A B3.8 2.1E-04 0742\n" + "1760 + 1544 1544 1546 SAG G RBR 245 380 0742\n" + "1760 + 1544 //// 1545 SAG C RSP 030-180 III/1 0742\n" + "1760 1546 1550 1553 G12 5 XFL S07W54 4.8E+02 1.0E+03 0742\n\n" + "1770 1633 //// 1634 SAG C RSP 030-050 III/1 \n\n" + "1780 1755 //// 1756 SAG C RSP 030-053 III/1 \n\n" + "1790 + 1851 //// 1851 PAL C RSP 025-085 III/1 \n\n" + "1800 + 1947 1953 1959 G12 5 XRA 1-8A B5.9 3.3E-04 0742\n" + "1800 1952 1957 1957 G12 5 XFL S06W57 7.3E+02 1.8E+03 0742\n\n" + "1810 + 2029 2034 2036 G12 5 XRA 1-8A B5.3 1.6E-04 0742\n" + "1810 + 2030 //// 2032 CUL C RSP 20-350 III/2 0742\n" + "1810 B2033 2033 2035 G12 5 XFL S07W54 7.8E+02 2.0E+03 0742\n" + "1810 + 2035 2035 2035 PAL G RBR 245 110 0742\n" + "1810 2035 U2035 2035 PAL G RBR 410 63 0742\n\n" + "1820 + 2049 2053 2056 G12 5 XRA 1-8A B3.6 1.3E-04 0742\n" + "1820 2051 //// 2051 CUL C RSP 40-160 III/1 0742\n" + "1820 2053 2053 A2053 G12 5 XFL S02W55 1.8E+02 3.3E+02 0742\n\n" + "1830 + 2116 2116 2116 PAL G RBR 245 630 \n" + "1830 + 2116 2116 2116 PAL G RBR 410 130 \n" + "1830 2116 2116 2116 PAL G RBR 606 67 \n" + "1830 2116 //// 2116 CUL C RSP 40-460 III/2 \n\n" + "1840 + 2304 2314 2316 G12 5 XRA 1-8A B9.8 4.6E-04 0742\n" + "1840 2309 2313 2316 G12 5 XFL S07W56 2.0E+03 5.3E+03 0742\n" + "1840 2313 2313 2318 HOL 3 FLA S06W52 SF ERU 0742\n" + "1840 2313 //// 2315 PAL C RSP 025-180 V/1 0742\n" + "1840 + 2314 2314 2314 PAL G RBR 245 160 0742\n" + "1840 + 2314 2314 2314 PAL G RBR 410 1700 0742\n" + "1840 + 2314 //// 2315 CUL C RSP 18-500 III/3 0742\n"; 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