Regular Expressions 101

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  • Unit Tests (17)

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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 single character of: a, b, c or d
    [[ab][cd]]
  • 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]
  • Character class intersection
    [\w&&[^\d]]
  • 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

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?:(?:import|export)[^`'\"]*from\\s+[`'\"])(?<from>[^`'\"./][^`'\"]*)(?:[`'\"])|(?:\\bimport)(?:\\s+|\\s*\\(\\s*)(?:[`'\"])(?<plain>[^`'\"./][^`'\"]*)(?:[`'\"])"; final String string = "import { defaultTemplateProcessor } from './lib/default-template-processor.js';\n" + "import { SVGTemplateResult, TemplateResult } from './lib/template-result.js';\n" + "export { DefaultTemplateProcessor, defaultTemplateProcessor } from './lib/default-template-processor.js';\n" + "export { directive, isDirective } from './lib/directive.js';\n" + "export { removeNodes, reparentNodes } from './lib/dom.js';\n" + "export { noChange, nothing } from './lib/part.js';\n" + "export { AttributeCommitter, AttributePart, BooleanAttributePart, EventPart, isIterable, isPrimitive, NodePart, PropertyCommitter, PropertyPart } from './lib/parts.js';\n" + "export { parts, render } from './lib/render.js';\n" + "export { templateCaches, templateFactory } from './lib/template-factory.js';\n" + "export { TemplateInstance } from './lib/template-instance.js';\n" + "export { SVGTemplateResult, TemplateResult } from './lib/template-result.js';\n" + "export { createMarker, isTemplatePartActive, Template } from './lib/template.js';\n" + "import { render } from 'lit-html/lib/shady-render.js';\n" + "import { UpdatingElement } from './lib/updating-element.js';\n" + "export * from './lib/updating-element.js';\n" + "export * from './lib/decorators.js';\n" + "export { html, svg, TemplateResult, SVGTemplateResult } from 'lit-html/lit-html.js';\n" + "import { supportsAdoptingStyleSheets } from './lib/css-tag.js';\n" + "export * from './lib/css-tag.js';\n" + "import { LitElement } from 'lit-element';\n" + "import { IronMeta } from '@polymer/iron-meta/iron-meta.js';\n" + "import { whenOnline } from 'hadron-core/lib/utils/async.js';\n" + "import { apiUrl, apiVersion } from '../../src/config.js';\n" + "import { importModule, dynamicImportAvailable } from '../../src/dynamic-imports-polyfill.js';\n" + "import observeProperties from 'hadron-core/lib/utils/object-property-observer.js';\n" + "export { version };\n" + "import { ElementMixin, version } from './lib/mixins/element-mixin.js';\n" + "export { html } from './lib/utils/html-tag.js';\n\n" + "class Foo {\n\n" + " constructor() {\n" + " import(`foo.js`);\n" + " import(`${foo}`);\n" + " import('bar.js');\n" + " } \n\n" + "}"; 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