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
Processing...

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 = "^[\\w\\d-]*(?=\\=)"; final String string = "# This file may be used to create an environment using:\n" + "# $ conda create --name <env> --file <this file>\n" + "# platform: osx-64\n" + "absl-py=0.7.1=py36_0\n" + "appnope=0.1.0=py36_1000\n" + "asn1crypto=0.24.0=py36_1003\n" + "astor=0.7.1=py_0\n" + "attrs=19.1.0=py_0\n" + "backcall=0.1.0=py_0\n" + "bleach=3.1.0=py_0\n" + "blinker=1.4=py_1\n" + "boto=2.49.0=py_0\n" + "boto3=1.9.210=py_0\n" + "botocore=1.12.210=py_0\n" + "bz2file=0.98=py_0\n" + "c-ares=1.15.0=h01d97ff_1001\n" + "ca-certificates=2019.6.16=hecc5488_0\n" + "certifi=2019.6.16=py36_1\n" + "cffi=1.12.3=py36hccf1714_0\n" + "chardet=3.0.4=py36_1003\n" + "cryptography=2.7=py36h212c5bf_0\n" + "cycler=0.10.0=py_1\n" + "cymem=2.0.2=py36h6de7cb9_0\n" + "cython-blis=0.2.4=py36h01d97ff_1\n" + "decorator=4.4.0=py_0\n" + "defusedxml=0.5.0=py_1\n" + "docutils=0.15.2=py36_0\n" + "en-core-web-lg=2.1.0=pypi_0\n" + "en-core-web-md=2.1.0=pypi_0\n" + "en-core-web-sm=2.1.0=pypi_0\n" + "entrypoints=0.3=py36_1000\n" + "freetype=2.10.0=h24853df_1\n" + "funcy=1.13=py_0\n" + "future=0.17.1=py36_1000\n" + "gast=0.2.2=py_0\n" + "gensim=3.4.0=py36h1de35cc_0\n" + "grpcio=1.22.0=py36h6ef0057_0\n" + "h5py=2.9.0=nompi_py36h6248fd5_1104\n" + "hdf5=1.10.5=nompi_h0cbb7df_1100\n" + "idna=2.8=py36_1000\n" + "ipykernel=5.1.2=py36h5ca1d4c_0\n" + "ipython=7.7.0=py36h5ca1d4c_0\n" + "ipython_genutils=0.2.0=py_1\n" + "jedi=0.15.1=py36_0\n" + "jinja2=2.10.1=py_0\n" + "jmespath=0.9.4=py_0\n" + "joblib=0.13.2=py_0\n" + "jpeg=9c=h1de35cc_1001\n" + "jsonschema=3.0.2=py36_0\n" + "jupyter_client=5.3.1=py_0\n" + "jupyter_core=4.4.0=py_0\n" + "keras-applications=1.0.7=py_1\n" + "keras-preprocessing=1.0.9=py_1\n" + "kiwisolver=1.1.0=py36h770b8ee_0\n" + "libblas=3.8.0=12_openblas\n" + "libcblas=3.8.0=12_openblas\n" + "libcxx=8.0.0=4\n" + "libcxxabi=8.0.0=4\n" + "libffi=3.2.1=h6de7cb9_1006\n" + "libgfortran=3.0.1=0\n" + "liblapack=3.8.0=12_openblas\n" + "libopenblas=0.3.7=hd44dcd8_1\n" + "libpng=1.6.37=h2573ce8_0\n" + "libprotobuf=3.9.1=hfbae3c0_0\n" + "libsodium=1.0.17=h01d97ff_0\n" + "libtiff=4.0.10=hd08fb8f_1003\n" + "lz4-c=1.8.3=h6de7cb9_1001\n" + "markdown=3.1.1=py_0\n" + "markupsafe=1.1.1=py36h1de35cc_0\n" + "matplotlib-base=3.1.1=py36h3a684a6_1\n" + "mistune=0.8.4=py36h1de35cc_1000\n" + "murmurhash=1.0.0=py36h0a44026_0\n" + "nbconvert=5.6.0=py_0\n" + "nbformat=4.4.0=py_1\n" + "ncurses=6.1=h0a44026_1002\n" + "nltk=3.4.4=py_0\n" + "notebook=6.0.0=py36_0\n" + "numexpr=2.7.0=py36h86efe34_0\n" + "numpy=1.17.0=py36h6b0580a_0\n" + "oauthlib=3.0.1=py_0\n" + "olefile=0.46=py_0\n" + "openssl=1.1.1c=h01d97ff_0\n" + "pandas=0.25.0=py36h86efe34_0\n" + "pandoc=2.7.3=0\n" + "pandocfilters=1.4.2=py_1\n" + "parso=0.5.1=py_0\n" + "patsy=0.5.1=py_0\n" + "pexpect=4.7.0=py36_0\n" + "pickleshare=0.7.5=py36_1000\n" + "pip=19.2.2=py36_0\n" + "plac=0.9.6=py36_0\n" + "preshed=2.0.1=py36h6de7cb9_0\n" + "prometheus_client=0.7.1=py_0\n" + "prompt_toolkit=2.0.9=py_0\n" + "protobuf=3.9.1=py36h6de7cb9_0\n" + "ptyprocess=0.6.0=py_1001\n" + "pycountry=19.8.18=pypi_0\n" + "pycparser=2.19=py36_1\n" + "pygments=2.4.2=py_0\n" + "pyjwt=1.7.1=py_0\n" + "pyopenssl=19.0.0=py36_0\n" + "pyparsing=2.4.2=py_0\n" + "pyrsistent=0.15.4=py36h01d97ff_0\n" + "pysocks=1.7.0=py36_0\n" + "python=3.6.7=h94afb7f_1005\n" + "python-dateutil=2.8.0=py_0\n" + "pytz=2019.2=py_0\n" + "pyzmq=18.0.2=py36hee98d25_2\n" + "readline=8.0=hcfe32e1_0\n" + "requests=2.22.0=py36_1\n" + "requests-oauthlib=1.2.0=py_0\n" + "retrying=1.3.3=py_2\n" + "s3transfer=0.2.1=py36_0\n" + "scipy=1.3.1=py36hab3da7d_2\n" + "seaborn=0.9.0=py_1\n" + "send2trash=1.5.0=py_0\n" + "setuptools=41.0.1=py36_0\n" + "simplejson=3.16.1=py36h470a237_0\n" + "six=1.12.0=py36_1000\n" + "smart_open=1.8.4=py_0\n" + "snowballstemmer=1.9.0=py_0\n" + "sortedcollections=1.1.2=py_0\n" + "sortedcontainers=2.1.0=py_0\n" + "spacy=2.1.8=py36h770b8ee_0\n" + "sqlite=3.29.0=hb7d70f7_0\n" + "srsly=0.0.7=py36h6de7cb9_0\n" + "statsmodels=0.10.1=py36heacc8b8_0\n" + "sumy=0.8.1=pypi_0\n" + "tensorboard=1.13.1=py36_0\n" + "tensorflow=1.13.1=py36_1\n" + "tensorflow-estimator=1.13.0=py36h24bf2e0_0\n" + "termcolor=1.1.0=py_2\n" + "terminado=0.8.2=py36_0\n" + "testpath=0.4.2=py_1001\n" + "thinc=7.0.8=py36h770b8ee_0\n" + "tk=8.6.9=h2573ce8_1002\n" + "tornado=6.0.3=py36h01d97ff_0\n" + "tqdm=4.33.0=py_0\n" + "traitlets=4.3.2=py36_1000\n" + "tweepy=3.8.0=py_0\n" + "urllib3=1.25.3=py36_0\n" + "wasabi=0.2.2=py_0\n" + "wcwidth=0.1.7=py_1\n" + "webencodings=0.5.1=py_1\n" + "werkzeug=0.15.5=py_0\n" + "wheel=0.33.4=py36_0\n" + "xz=5.2.4=h1de35cc_1001\n" + "zeromq=4.3.2=h6de7cb9_2\n" + "zlib=1.2.11=h01d97ff_1005\n" + "zstd=1.4.0=ha9f0a20_0"; 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