Regular Expressions 101

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  • 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"
"
gm

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"\-*?\n(\d{1,2}(?:\s+[+-]?\d.*?)+)?\n\w+.*?([+-]?\d+\.\d+)\n\w.*?\n\w+\s(\d+).*?\n\w.*\n" test_str = ("--------------------------------------------------------\n" "6 0.934039 1.910373 -0.007356\n" "6 0.522681 1.025902 1.132490\n" "6 1.295895 0.175184 1.887754\n" "6 2.745917 -0.059133 1.663889\n" "6 3.251755 -1.317777 1.620723\n" "6 2.354786 -2.503163 1.659226\n" "6 2.500165 -3.540741 2.548878\n" "16 1.200827 -4.674482 2.398451\n" "6 0.450003 -3.761272 1.124048\n" "6 1.191704 -2.653037 0.838883\n" "1 0.889391 -1.914706 0.104995\n" "6 -0.831020 -4.156701 0.527821\n" "6 -1.110322 -3.881221 -0.814127\n" "6 -2.349055 -4.235426 -1.332810\n" "7 -3.309523 -4.841208 -0.630339\n" "6 -3.035523 -5.105663 0.648864\n" "6 -1.833017 -4.789011 1.269474\n" "1 -1.692631 -5.008941 2.323469\n" "1 -3.826405 -5.592591 1.215268\n" "1 -2.579432 -4.028326 -2.375778\n" "1 -0.365461 -3.412291 -1.448955\n" "6 3.573349 -3.754217 3.574993\n" "1 3.816975 -2.812111 4.074804\n" "1 3.260231 -4.473156 4.337010\n" "1 4.494421 -4.124194 3.111155\n" "6 4.710061 -1.617156 1.557050\n" "6 5.623546 -1.003416 2.421004\n" "6 6.974181 -1.326012 2.370518\n" "6 7.436595 -2.269579 1.456291\n" "6 6.535520 -2.894414 0.598497\n" "6 5.182590 -2.576469 0.655016\n" "1 4.479434 -3.078256 -0.004163\n" "1 6.885058 -3.634965 -0.114866\n" "1 8.492504 -2.519869 1.416345\n" "1 7.667827 -0.841306 3.051107\n" "1 5.267975 -0.268736 3.136940\n" "6 3.580944 1.164538 1.503126\n" "6 4.497172 1.300372 0.454818\n" "6 5.240591 2.465784 0.310519\n" "6 5.081537 3.515835 1.211519\n" "6 4.166656 3.395074 2.253939\n" "6 3.418260 2.231401 2.393481\n" "1 2.692677 2.145384 3.197718\n" "1 4.033033 4.209217 2.960243\n" "1 5.661476 4.426693 1.096865\n" "1 5.945953 2.554610 -0.510417\n" "1 4.622653 0.485776 -0.251950\n" "6 0.528985 -0.506746 2.884231\n" "6 -0.800876 -0.209971 2.864388\n" "16 -1.134679 0.961768 1.625169\n" "6 -1.858335 -0.812159 3.682689\n" "6 -1.740268 -2.136749 4.118466\n" "6 -2.752842 -2.684280 4.894687\n" "7 -3.862544 -2.030644 5.248979\n" "6 -3.974818 -0.772056 4.819134\n" "6 -3.016393 -0.122197 4.049880\n" "1 -3.167697 0.912109 3.755521\n" "1 -4.882415 -0.247888 5.110965\n" "1 -2.672356 -3.711555 5.245040\n" "1 -0.881625 -2.737495 3.833528\n" "1 0.964846 -1.208304 3.585910\n" "1 0.076921 2.185394 -0.628553\n" "1 1.403779 2.830811 0.357050\n" "1 1.665791 1.402320 -0.641683\n" "Energy (Hartree) = -2216.64927779\n" "Step: 34\n" "Scan 1 out of 73\n" "Converged(Max Force, RMS Force, Max Disp, RMS Disp): YES, YES, NO, YES\n" "--------------------------------------------------------\n\n" "--------------------------------------------------------\n" "6 0.934062 1.911021 -0.006793\n" "6 0.522693 1.026243 1.132808\n" "6 1.295849 0.175204 1.887786\n" "6 2.745849 -0.059151 1.663825\n" "6 3.251670 -1.317799 1.620645\n" "6 2.354637 -2.503134 1.659254\n" "6 2.499913 -3.540512 2.549163\n" "16 1.200720 -4.674404 2.398679\n" "6 0.450032 -3.761466 1.124001\n" "6 1.191706 -2.653228 0.838749\n" "1 0.889499 -1.915053 0.104660\n" "6 -0.830799 -4.157197 0.527556\n" "6 -1.109977 -3.881704 -0.814420\n" "6 -2.348529 -4.236224 -1.333319\n" "7 -3.308924 -4.842349 -0.631043\n" "6 -3.035027 -5.106853 0.648170\n" "6 -1.832715 -4.789884 1.268992\n" "1 -1.692398 -5.009943 2.322969\n" "1 -3.825839 -5.594087 1.214409\n" "1 -2.578819 -4.029095 -2.376300\n" "1 -0.365153 -3.412510 -1.449097\n" "6 3.572924 -3.753599 3.575540\n" "1 3.816308 -2.811319 4.075158\n" "1 3.259759 -4.472389 4.337671\n" "1 4.494142 -4.123544 3.111975\n" "6 4.709955 -1.617231 1.556911\n" "6 5.623512 -1.003434 2.420751\n" "6 6.974133 -1.326076 2.370222\n" "6 7.436469 -2.269740 1.456057\n" "6 6.535326 -2.894639 0.598379\n" "6 5.182409 -2.576651 0.654945\n" "1 4.479201 -3.078478 -0.004148\n" "1 6.884808 -3.635261 -0.114937\n" "1 8.492367 -2.520070 1.416076\n" "1 7.667829 -0.841314 3.050721\n" "1 5.268008 -0.268672 3.136635\n" "6 3.580909 1.164495 1.503041\n" "6 4.497111 1.300286 0.454710\n" "6 5.240549 2.465680 0.310363\n" "6 5.081547 3.515754 1.211345\n" "6 4.166716 3.395021 2.253815\n" "6 3.418302 2.231369 2.393405\n" "1 2.692762 2.145371 3.197682\n" "1 4.033146 4.209176 2.960116\n" "1 5.661485 4.426605 1.096636\n" "1 5.945883 2.554473 -0.510601\n" "1 4.622556 0.485666 -0.252039\n" "6 0.528927 -0.506827 2.884183\n" "6 -0.800849 -0.209681 2.864659\n" "16 -1.134600 0.962406 1.625752\n" "6 -1.858353 -0.811785 3.682977\n" "6 -1.740809 -2.136677 4.117983\n" "6 -2.753416 -2.684132 4.894214\n" "7 -3.862669 -2.030122 5.249222\n" "6 -3.974426 -0.771225 4.820153\n" "6 -3.015920 -0.121422 4.050946\n" "1 -3.166775 0.913141 3.757259\n" "1 -4.881643 -0.246746 5.112609\n" "1 -2.673367 -3.711662 5.243914\n" "1 -0.882533 -2.737672 3.832462\n" "1 0.964690 -1.208688 3.585621\n" "1 0.076974 2.186246 -0.627940\n" "1 1.403854 2.831315 0.357930\n" "1 1.665819 1.403131 -0.641235\n" "Energy (Hartree) = -2216.64927781\n" "Step: 35\n" "Scan 1 out of 73\n" "Converged(Max Force, RMS Force, Max Disp, RMS Disp): YES, YES, YES, YES\n" "Optimized Parameters for Coordinate Value: 48.7864\n" "--------------------------------------------------------\n\n" "--------------------------------------------------------\n" "6 0.928653 1.914728 -0.015952\n" "6 0.523104 1.029664 1.125513\n" "6 1.299323 0.175435 1.873723\n" "6 2.746979 -0.062752 1.638872\n" "6 3.250582 -1.322711 1.610272\n" "6 2.350949 -2.505931 1.653003\n" "6 2.487964 -3.535693 2.553022\n" "16 1.187646 -4.668406 2.403419\n" "6 0.447689 -3.765331 1.115501\n" "6 1.193508 -2.661056 0.825700\n" "1 0.897892 -1.928805 0.083033\n" "6 -0.829701 -4.163896 0.513583\n" "6 -1.098964 -3.899654 -0.832683\n" "6 -2.334534 -4.256414 -1.357129\n" "7 -3.300974 -4.854584 -0.656318\n" "6 -3.036531 -5.108382 0.627053\n" "6 -1.837984 -4.788211 1.253491\n" "1 -1.705454 -4.999308 2.310312\n" "1 -3.832212 -5.589178 1.191978\n" "1 -2.557135 -4.057999 -2.403474\n" "1 -0.348825 -3.437415 -1.466208\n" "6 3.553334 -3.741710 3.588769\n" "1 3.794918 -2.795527 4.081850\n" "1 3.233495 -4.453260 4.354918\n" "1 4.477112 -4.117327 3.134952\n" "6 4.708676 -1.625521 1.559405\n" "6 5.617384 -1.005953 2.424241\n" "6 6.967681 -1.331651 2.386026\n" "6 7.434526 -2.284193 1.483422\n" "6 6.538165 -2.914834 0.624932\n" "6 5.185521 -2.593731 0.669206\n" "1 4.485944 -3.099951 0.009606\n" "1 6.891156 -3.662361 -0.079406\n" "1 8.490177 -2.536916 1.453052\n" "1 7.657559 -0.842289 3.067116\n" "1 5.258339 -0.264251 3.131155\n" "6 3.588296 1.158822 1.495804\n" "6 4.455584 1.334979 0.412017\n" "6 5.190024 2.506923 0.274817\n" "6 5.065591 3.527255 1.214482\n" "6 4.191377 3.371568 2.286682\n" "6 3.451948 2.201349 2.419198\n" "1 2.755016 2.090210 3.245500\n" "1 4.081099 4.164280 3.020955\n" "1 5.637641 4.443718 1.104935\n" "1 5.859723 2.624932 -0.572054\n" "1 4.551226 0.545487 -0.327323\n" "6 0.537765 -0.505652 2.874875\n" "6 -0.791246 -0.204606 2.865525\n" "16 -1.130701 0.970006 1.630565\n" "6 -1.844454 -0.804660 3.690867\n" "6 -1.727716 -2.130536 4.123087\n" "6 -2.736173 -2.676023 4.906078\n" "7 -3.840730 -2.019138 5.270315\n" "6 -3.951832 -0.759281 4.843904\n" "6 -2.997115 -0.111294 4.068471\n" "1 -3.146985 0.924153 3.777407\n" "1 -4.855222 -0.232457 5.143904\n" "1 -2.656671 -3.704306 5.253685\n" "1 -0.873433 -2.733722 3.830294\n" "1 0.976622 -1.209660 3.572222\n" "1 0.067886 2.192910 -0.630666\n" "1 1.403422 2.833365 0.346506\n" "1 1.654564 1.405702 -0.656173\n" "Energy (Hartree) = -2216.64908578\n" "Step: 1\n" "Scan 2 out of 73\n" "Converged(Max Force, RMS Force, Max Disp, RMS Disp): NO, YES, NO, NO\n" "--------------------------------------------------------") matches = re.finditer(regex, test_str, 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