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

/
/
g

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"assertEquals\(([^,]+),\s(.+)\);"; string substitution = @"assertEquals\($2\, $1\);"; string input = @"package com.gdit.fwa.informant.model.definitions; import static org.junit.Assert.assertEquals; import org.junit.Test; import com.gdit.fwa.informant.model.base.definition.RelationalOperator; import com.gdit.fwa.informant.model.base.definition.SqlConstants; @SuppressWarnings(""static-method"") public class RelationalOperatorTest { @Test public void testGetRelOperatorSql() { assertEquals(RelationalOperator.DEFAULT.getRelOperatorSql(), ""); assertEquals(RelationalOperator.IS.getRelOperatorSql(), ""IS""); assertEquals(RelationalOperator.IS_NOT.getRelOperatorSql(), ""IS NOT""); assertEquals(RelationalOperator.EQUAL.getRelOperatorSql(), ""=""); assertEquals(RelationalOperator.NOT_EQUAL.getRelOperatorSql(), ""<>""); assertEquals(RelationalOperator.GREATER_THAN.getRelOperatorSql(), "">""); assertEquals(RelationalOperator.LESS_THAN.getRelOperatorSql(), ""<""); assertEquals(RelationalOperator.GREATER_EQUAL.getRelOperatorSql(), "">=""); assertEquals(RelationalOperator.LESS_EQUAL.getRelOperatorSql(), ""<=""); assertEquals(RelationalOperator.BETWEEN.getRelOperatorSql(), ""BETWEEN""); assertEquals(RelationalOperator.IN.getRelOperatorSql(), ""IN""); assertEquals(RelationalOperator.NOT_IN.getRelOperatorSql(), ""NOT IN""); assertEquals(RelationalOperator.LIKE.getRelOperatorSql(), ""LIKE""); assertEquals(RelationalOperator.NOT_LIKE.getRelOperatorSql(), ""NOT LIKE""); assertEquals(RelationalOperator.SOUNDS_LIKE.getRelOperatorSql(), ""SOUNDS LIKE""); } @Test public void testGetRelationalOperator() { assertEquals(RelationalOperator.DEFAULT, RelationalOperator.getRelationalOperator("")); assertEquals(RelationalOperator.IS, RelationalOperator.getRelationalOperator(""IS"")); assertEquals(RelationalOperator.IS_NOT, RelationalOperator.getRelationalOperator(""IS NOT"")); assertEquals(RelationalOperator.EQUAL, RelationalOperator.getRelationalOperator(""="")); assertEquals(RelationalOperator.NOT_EQUAL, RelationalOperator.getRelationalOperator(""<>"")); assertEquals(RelationalOperator.GREATER_THAN, RelationalOperator.getRelationalOperator("">"")); assertEquals(RelationalOperator.LESS_THAN, RelationalOperator.getRelationalOperator(""<"")); assertEquals(RelationalOperator.GREATER_EQUAL, RelationalOperator.getRelationalOperator("">="")); assertEquals(RelationalOperator.LESS_EQUAL, RelationalOperator.getRelationalOperator(""<="")); assertEquals(RelationalOperator.BETWEEN, RelationalOperator.getRelationalOperator(""BETWEEN"")); assertEquals(RelationalOperator.IN, RelationalOperator.getRelationalOperator(""IN"")); assertEquals(RelationalOperator.NOT_IN, RelationalOperator.getRelationalOperator(""NOT IN"")); assertEquals(RelationalOperator.LIKE, RelationalOperator.getRelationalOperator(""LIKE"")); assertEquals(RelationalOperator.NOT_LIKE, RelationalOperator.getRelationalOperator(""NOT LIKE"")); assertEquals(RelationalOperator.SOUNDS_LIKE, RelationalOperator.getRelationalOperator(""SOUNDS LIKE"")); } @Test public void testRelOpEqualityFunctions() { for (RelationalOperator relOp : RelationalOperator.values()) { if (relOp == RelationalOperator.IS || relOp == RelationalOperator.IS_NOT){ assertEquals(relOp.isEquality(), true); assertEquals(relOp.getNullLogicOperator(), SqlConstants.OR); assertEquals(relOp.getNullRelOperator(), RelationalOperator.IS); assertEquals(relOp.getRelOperatorFilterSql(), RelationalOperator.IN.getRelOperatorSql()); } else { assertEquals(relOp.isEquality(), false); assertEquals(relOp.getNullLogicOperator(), SqlConstants.AND); assertEquals(relOp.getNullRelOperator(), RelationalOperator.IS_NOT); assertEquals(relOp.getRelOperatorFilterSql(), RelationalOperator.NOT_IN.getRelOperatorSql()); } } } @Test @SuppressWarnings(""deprecation"") public void testGetNullValue() { assertEquals(RelationalOperator.getNullValue(), SqlConstants.NULL); } @Test public void testGetNullClause() { for (RelationalOperator relOp : RelationalOperator.values()) { switch (relOp) { case IS: case EQUAL: assertEquals(relOp.getNullClause(""Test""), "" OR Test IS null""); break; case IS_NOT: case NOT_EQUAL: assertEquals(relOp.getNullClause(""Test""), "" AND Test IS NOT null""); break; default: assertEquals(relOp.getNullClause(""Test""), ""); } } } } "; Regex regex = new Regex(pattern); string result = regex.Replace(input, 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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx