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

/
/
g

Test String

Substitution

Processing...

Code Generator

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"assertEquals\(([^,]+),\s(.+)\);").unwrap(); let string = "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\"), \"\"); } } } } "; let substitution = "assertEquals\\($2\\, $1\\);"; // result will be a String with the substituted value let result = regex.replace_all(string, substitution); println!("{}", result); }

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/