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

%
%
mg

Test String

Code Generator

Language

Generated Code

// include the latest version of the regex crate in your Cargo.toml extern crate regex; use regex::Regex; fn main() { let regex = Regex::new(r"(?m)^\D{8}(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)$").unwrap(); let string = "{\"log\":\"I1219 13:32:01.389913 1 server.go:114] Version: v1.8.0\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.390360472Z\"} {\"log\":\"I1219 13:32:01.390379 1 plugins.go:101] No cloud provider specified.\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.390969576Z\"} {\"log\":\"I1219 13:32:01.634232 1 feature_gate.go:156] feature gates: map[Initializers:true]\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.635347611Z\"} {\"log\":\"I1219 13:32:01.635456 1 initialization.go:84] enabled Initializers feature as part of admission plugin setup\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.635590586Z\"} {\"log\":\"W1219 13:32:01.636255 1 admission.go:66] PersistentVolumeLabel admission controller is deprecated. Please remove this controller from your configuration files and scripts.\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.636854971Z\"} {\"log\":\"W1219 13:32:01.713333 1 genericapiserver.go:317] Skipping API batch/v2alpha1 because it has no resources.\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.713583761Z\"} {\"log\":\"W1219 13:32:01.731298 1 genericapiserver.go:317] Skipping API rbac.authorization.k8s.io/v1alpha1 because it has no resources.\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.732776091Z\"} {\"log\":\"[restful] 2017/12/19 13:32:01 log.go:33: [restful/swagger] listing is available at https://185.150.9.204:6443/swaggerapi\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.799479979Z\"} {\"log\":\"[restful] 2017/12/19 13:32:01 log.go:33: [restful/swagger] https://185.150.9.204:6443/swaggerui/ is mapped to folder /swagger-ui/\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:01.799497746Z\"} {\"log\":\"[restful] 2017/12/19 13:32:02 log.go:33: [restful/swagger] listing is available at https://185.150.9.204:6443/swaggerapi\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:02.471721558Z\"} {\"log\":\"[restful] 2017/12/19 13:32:02 log.go:33: [restful/swagger] https://185.150.9.204:6443/swaggerui/ is mapped to folder /swagger-ui/\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:02.47174796Z\"} {\"log\":\"I1219 13:32:04.992367 1 serve.go:85] Serving securely on 0.0.0.0:6443\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993893788Z\"} {\"log\":\"I1219 13:32:04.992843 1 apiservice_controller.go:112] Starting APIServiceRegistrationController\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993922573Z\"} {\"log\":\"I1219 13:32:04.992865 1 cache.go:32] Waiting for caches to sync for APIServiceRegistrationController controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993925574Z\"} {\"log\":\"I1219 13:32:04.992909 1 available_controller.go:192] Starting AvailableConditionController\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993927705Z\"} {\"log\":\"I1219 13:32:04.992925 1 cache.go:32] Waiting for caches to sync for AvailableConditionController controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993929704Z\"} {\"log\":\"I1219 13:32:04.992944 1 crd_finalizer.go:242] Starting CRDFinalizer\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993931736Z\"} {\"log\":\"I1219 13:32:04.992949 1 customresource_discovery_controller.go:152] Starting DiscoveryController\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993933463Z\"} {\"log\":\"I1219 13:32:04.992953 1 naming_controller.go:277] Starting NamingConditionController\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993935376Z\"} {\"log\":\"I1219 13:32:04.992975 1 crdregistration_controller.go:112] Starting crd-autoregister controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993937164Z\"} {\"log\":\"I1219 13:32:04.992979 1 controller_utils.go:1041] Waiting for caches to sync for crd-autoregister controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.993939029Z\"} {\"log\":\"I1219 13:32:04.994147 1 controller.go:84] Starting OpenAPI AggregationController\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:04.994289148Z\"} {\"log\":\"I1219 13:32:05.092979 1 cache.go:39] Caches are synced for APIServiceRegistrationController controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:05.093392359Z\"} {\"log\":\"I1219 13:32:05.092978 1 cache.go:39] Caches are synced for AvailableConditionController controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:05.093418406Z\"} {\"log\":\"I1219 13:32:05.093102 1 controller_utils.go:1048] Caches are synced for crd-autoregister controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:05.093430972Z\"} {\"log\":\"I1219 13:32:05.093142 1 autoregister_controller.go:136] Starting autoregister controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:05.093433199Z\"} {\"log\":\"I1219 13:32:05.093146 1 cache.go:32] Waiting for caches to sync for autoregister controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:05.093435176Z\"} {\"log\":\"I1219 13:32:05.193207 1 cache.go:39] Caches are synced for autoregister controller\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:05.193541587Z\"} {\"log\":\"I1219 13:32:09.998168 1 trace.go:76] Trace[1836345649]: \\\"Create /api/v1/namespaces\\\" (started: 2017-12-19 13:32:05.995599565 +0000 UTC) (total time: 4.002539088s):\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:10.008954395Z\"} {\"log\":\"Trace[1836345649]: [4.000446951s] [4.000418303s] About to store object in database\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:10.008974063Z\"} {\"log\":\"I1219 13:32:10.629009 1 trace.go:76] Trace[1988456937]: \\\"Create /api/v1/namespaces/kube-system/events\\\" (started: 2017-12-19 13:32:06.625541932 +0000 UTC) (total time: 4.003444046s):\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:10.63530296Z\"} {\"log\":\"Trace[1988456937]: [4.001682236s] [4.001642828s] About to store object in database\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:10.635326659Z\"} {\"log\":\"I1219 13:32:11.593994 1 trace.go:76] Trace[1945366238]: \\\"Create /api/v1/nodes\\\" (started: 2017-12-19 13:32:07.591993863 +0000 UTC) (total time: 4.00197912s):\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:11.59759386Z\"} {\"log\":\"Trace[1945366238]: [4.000615689s] [4.000505107s] About to store object in database\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:11.597618565Z\"} {\"log\":\"I1219 13:32:12.651139 1 trace.go:76] Trace[648564056]: \\\"Create /api/v1/namespaces/kube-system/events\\\" (started: 2017-12-19 13:32:08.641834265 +0000 UTC) (total time: 4.009285942s):\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:12.65281182Z\"} {\"log\":\"Trace[648564056]: [4.001050787s] [4.001021095s] About to store object in database\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:12.652826332Z\"} {\"log\":\"I1219 13:32:14.684575 1 trace.go:76] Trace[1339119512]: \\\"Create /apis/authentication.k8s.io/v1/tokenreviews\\\" (started: 2017-12-19 13:32:10.677360533 +0000 UTC) (total time: 4.007189394s):\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:14.689524885Z\"} {\"log\":\"Trace[1339119512]: [4.004918437s] [4.004846143s] About to store object in database\\n\",\"stream\":\"stderr\",\"time\":\"2017-12-19T13:32:14.689537857Z\"} "; // result will be an iterator over tuples containing the start and end indices for each match in the string let result = regex.captures_iter(string); for mat in result { println!("{:?}", mat); } }

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 Rust, please visit: https://docs.rs/regex/latest/regex/