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

/
/
igm

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"([\d\.]+%) identity" test_str = ("# /data/spine/bin/external/fasta/bin/glsearch36 -b 2 -m 9i -q /tmp/temp.seq /data/spine/databases/UniProt/sprot.compact_headers.distinct.mouse\n" "GLSEARCH performs a global-query/local-library search\n" " version 36.3.6 Nov, 2013(preload9)\n" "Query: /tmp/temp.seq\n" " 1>>>seq - 299 aa\n" "Library: /data/spine/databases/UniProt/sprot.compact_headers.distinct.mouse\n" " 9277236 residues in 16315 sequences\n\n" "Statistics: Unscaled normal statistics: mu= -50.7059 var=2892.0306 Ztrim: 0\n" " statistics sampled from 13365 (13367) to 13365 sequences\n" "Algorithm: Global/Local affine Needleman-Wunsch (2007) (6.0 April 2007)\n" "Parameters: BL50 matrix (15:-5), open/ext: -12/-2\n" " Scan time: 11.560\n\n" "The best scores are: n-w bits E(16315) %_id %_sim alen\n" "SP|P61375|LHX5_MOUSE ( 402) 1361 66.3 5.7e-148 0.685 0.868 302\n" "SP|P50481|LHX3_MOUSE ( 400) 331 30.8 1e-08 0.319 0.524 307\n\n" ">>>seq, 299 aa vs /data/spine/databases/UniProt/sprot.compact_headers.distinct.mouse library\n\n" ">>SP|P61375|LHX5_MOUSE (402 aa)\n" " n-w opt: 1361 Z-score: 312.5 bits: 66.3 E(16315): 5.7e-148\n" "global/local score: 1361; 68.5% identity (86.8% similar) in 302 aa overlap (1-299:107-400)\n\n" " 10 20 30\n" "seq YIDENKFVCKEDYLSNSSVAKENSLHSATT\n" " :::::::::.::::.::. ::.::.:...\n" "SP|P61 VRKARSKVFHLNCFTCMVCNKQLSTGEELYVIDENKFVCKDDYLSSSSL-KEGSLNSVSS\n" " 80 90 100 110 120 130 \n\n" " 40 50 60 70 80 90\n" "seq GSDPSLSPDSQDPSQDDAKDSESANVSDKEGGSNENDDQNLGAKRRGPRTTIKAKQLETL\n" " .: ::::: ::: ::: :...... :::: ..:::..:: :.:::::::::::::::::\n" "SP|P61 CTDRSLSPDLQDPLQDDPKETDNSTSSDKETANNENEEQNSGTKRRGPRTTIKAKQLETL\n" " 140 150 160 170 180 190 \n\n" " 100 110 120 130 140 150\n" "seq KAAFAATPKPTRHIREQLAQETGLNMRVIQVWFQNRRSKERRMKQLSALGARRHAFFRSP\n" " ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::\n" "SP|P61 KAAFAATPKPTRHIREQLAQETGLNMRVIQVWFQNRRSKERRMKQLSALGARRHAFFRSP\n" " 200 210 220 230 240 250 \n\n" " 160 170 180 190 200 210\n" "seq RRMRPLVDRLEPGELIPNGPFSFYGDYQSEYYGPGGNYDFFPQGPPSSQAQTPVDLPFVP\n" " :::::: ::. .:.. . :...::::::.::.:::::::: .:::: :::.:.: :. \n" "SP|P61 RRMRPLGGRLDESEMLGSTPYTYYGDYQSDYYAPGGNYDFFAHGPPS-QAQSPADSSFLA\n" " 260 270 280 290 300 310 \n\n" " 220 230 240 250 260 \n" "seq SSGPSGTPLGGLDHPLPGHHPSSEAQRFTDILAHPPGDSPSPEPSLPGPLHSMSAEVF--\n" " .:::..::::.:. :: : : ... ::::...:: :.:::::.::: :: : .::: \n" "SP|P61 ASGPGSTPLGALEPPLAGPH-GADNPRFTDMISHP--DTPSPEPGLPGALHPMPGEVFSG\n" " 320 330 340 350 360 370 \n\n" " 270 280 290 \n" "seq GPSPPFSSLSVNGGASYGNHLSHP-PEMNEAA \n" " :::::: ..: ..:.. :::: ::.:::: \n" "SP|P61 GPSPPFP---MSGTSGYSGPLSHPNPELNEAAVW\n" " 380 390 400 \n\n" ">>SP|P50481|LHX3_MOUSE (400 aa)\n" " n-w opt: 331 Z-score: 121.0 bits: 30.8 E(16315): 1e-08\n" "global/local score: 331; 31.9% identity (52.4% similar) in 307 aa overlap (1-299:99-365)\n\n" " 10 20 \n" "seq YIDENKFVCK-EDYLSN-SSVAKENSLHSA\n" " : .. : . .:.. . : .. \n" "SP|P50 AERCFSRGESVYCKDDFFKRFGTKCAACQLGIPPTQVVRRAQDFVYHLHCFACVVCKRQL\n" " 70 80 90 100 110 120 \n\n" " 30 40 50 60 70 80 \n" "seq TTGSDPSLSPDSQDPSQDDAKDSESANVSDKEGGSNENDDQNLGAKRRGPRTTIKAKQLE\n" " .::.. : ::. . : :.:. . :. ::: ::::: :::::\n" "SP|P50 ATGDEFYLMEDSRLVCK---ADYETAKQREAEAT----------AKR--PRTTITAKQLE\n" " 130 140 150 160 170 \n\n" " 90 100 110 120 130 140 \n" "seq TLKAAFAATPKPTRHIREQLAQETGLNMRVIQVWFQNRRSKERRMKQLSALGARRHAFFR\n" " :::.:. ..:::.::.::::..::::.:::.::::::::.::.:.:. .: : .::\n" "SP|P50 TLKSAYNTSPKPARHVREQLSSETGLDMRVVQVWFQNRRAKEKRLKK-DAGRQRWGQYFR\n" " 180 190 200 210 220 230 \n\n" " 150 160 170 180 190 200 \n" "seq SPRRMRPLVDRLEPGELIPNGPFSFYGDYQSEYYGPGGNYDFFPQGPPSSQAQTPVDLPF\n" " . .: : : .: .: : .. . :: . :.. .\n" "SP|P50 NMKRSRG----------------SSKSDKDSIQEGQDSDAEVSFTDEPSMADMGPANGLY\n" " 240 250 260 270 \n\n" " 210 220 230 240 250 260 \n" "seq VPSSGPS---GTPLGGLDHPLPGHHPSSEAQRFTDILAHPP-GDSPSPEP--SLPGPLHS\n" " . :. : :.::: : . ... .. : : ::: ::::: \n" "SP|P50 SSLGEPAPALGRPVGGLGSFTLDHGGLTGPEQYRELRPGSPYGIPPSPAAPQSLPGPQPL\n" " 280 290 300 310 320 330 \n\n" " 270 280 290 \n" "seq MSAEVFGPSPPFSSLSVNGGASYGNHLSHPPEMNEAA \n" " .:. :. : ..::. .. :. :: : : \n" "SP|P50 LSSLVY----PDTNLSLVPSGPPGG----PPPMRVLAGNGPSSDLSTESSSGYPDFPASP\n" " 340 350 360 370 380 \n\n" "SP|P50 ASWLDEVDHAQF\n" " 390 400\n\n\n" ">>>///\n\n" "299 residues in 1 query sequences\n" "9277236 residues in 16315 library sequences\n" " Tcomplib [36.3.6 Nov, 2013(preload9)] (8 proc in memory [0G])\n" " start: Thu Sep 3 20:44:48 2015 done: Thu Sep 3 20:44:55 2015\n" " Total Scan time: 11.560 Total Display time: 0.010\n\n" "Function used was GLSEARCH [36.3.6 Nov, 2013(preload9)]") 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