Regular Expressions in Java

Package com.stevesoft.pat version 1.5.3


Home
Articles/Links
Mugs, T-shirts Comments/Raves
New in 1.5.3
A Game
An Online Test
Questions

Copyright/License
Download Free

 If you need a non-LGPL version
You Can Buy!

Online help...
Quick Start
Tutorial Part 1
Tutorial Part 2
Tutorial Part 3
Tutorial Part 4
Tutorial Part 5
Tutorial Part 6
Examples
Support
FAQ
Documentation

Useful apps...
Java Beautifier
Code Colorizer
GUI Grep
Swing Grep

Other stuff...
Phreida
xmlser

Column 1 contains a pattern example, the primary class name that implements it is in column 2, and an explanation of what the pattern does is in column 3. their descriptions
PatternClass NameExplanation
[a-c]RangeThis matches any character in the range 'a' to 'c'
[a-cde]BracketThis matches any character in the range 'a' to 'e'
[\-x]BracketThis matches the '-' character or the 'x' character
[^ab]BracketThis matches any characters except 'a' or 'b'
.AnyThis matches any character except \n. To match any character at all, you might try [\d\D].
{n1,n2}MultiThis matches between n1 and n2 instances of the previous Pattern, where n1 and n2 are integers.
{n1,}MultiThis matches at least n1 instances of the previous Pattern
*MultiThe same as {0,}
?MultiThe same as {0,1}
+MultiThe same as {1,}
*?MultiMinBy default, {n1,n2}, {n1,}, *, ?, +, match the largest number of occurences of the preceeding Pattern. If any of these is followed by a ? it will attempt, instead, to match the fewest occurents of the preceeding Pattern.
(a|b)OrMarkThis matches the character a or b, and returns the matched character as a backreference. In other words, if you call Regex's search method with "a" you will find that an "a" is returned by stringMatched(1).
(a)OrMarkThis matches the character "a" as a backreference.
\bBoundaryThis matches a word boundary, either a beginning \w character, an ending \w character, or one of these two sequences: \w\W, \W\w.
(?: ... )Orlike the parenthesis above, but does not create a backreference.
(?= ... )lookAheadA zero-length lookahead. Thus the pattern "foo(?=bar)" will match "foo", but only if followed by "bar".
(?! ... )lookAheadAnother form of zero-length lookahead. However, it only matches if the thing in the ()'s is not matched. Thus "foo(?!bar)" matches "foo" only if it is not followed by "bar".
(?# ... )A comment
\BBoundaryA non-word Boundary. Essentially the same as (?!\b).
\dRangeEssentially the same as [0-9].
\DBracketNot a digit. Essentially the same as [^0-9].
\wBracketA word character, essentially the same as [a-zA-Z_0-9]
\WBracketNot a word character.
\sBracketA white-space character, [ \t\b\n\r].
\SBracketA non white-space character.
\1BackMatchMatch the contents of the first backreference. Thus "([a-d]).*\1" matches the first 5 characters of "axyzabc".
(?i)Tell this pattern to ignore case during a match.
$EndMatches the end of a String (the \n character is considered the end of the string by this pattern element).
\ZEndMatches the end of a String. The \n character does not count as the end.
^StartMatches the beginning of a String. This is either the absolute beginning, or right after a \n character.
\AStartMatches the absolute beginning of a String.
\GBackGMatches the place we left off in our last search of this String with this pattern or, failing that, the beginning of the String.
For special unicode patterns click here.
Return to home page.