Java : MatchResult (regex) with Examples

MatchResult (Java SE 22 & JDK 22) with Examples.
You will find code examples on most MatchResult methods.

Summary

The result of a match operation.

Class diagram

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc 345");

final var stream = matcher.results();

stream.forEach(matchResult -> {

    System.out.println("------");
    System.out.println("start : " + matchResult.start());
    System.out.println("end : " + matchResult.end());
    System.out.println("group : " + matchResult.group());
});

// Result
// ↓
//------
//start : 0
//end : 3
//group : abc
//------
//start : 8
//end : 14
//group : aaaabc

Methods

int end ()

Returns the offset after the last character matched.

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc");

System.out.println(matcher.lookingAt()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 3
System.out.println(matchResult.group()); // "abc"

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc 345");

final var stream = matcher.results();

stream.forEach(matchResult -> {

    System.out.println("------");
    System.out.println("start : " + matchResult.start());
    System.out.println("end : " + matchResult.end());
    System.out.println("group : " + matchResult.group());
});

// Result
// ↓
//------
//start : 0
//end : 3
//group : abc
//------
//start : 8
//end : 14
//group : aaaabc

int end (int group)

Returns the offset after the last character of the subsequence captured by the given group during this match.

final var pattern = Pattern.compile("(abc|efg)_012_(x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

final var groupCount = matchResult.groupCount();
System.out.println(groupCount); // 2

for (int i = 1; i <= groupCount; i++) {

    System.out.println("------");
    System.out.println("i : " + i);
    System.out.println("start : " + matchResult.start(i));
    System.out.println("end : " + matchResult.end(i));
    System.out.println("group : " + matchResult.group(i));
}

// Result
// ↓
//------
//i : 1
//start : 0
//end : 3
//group : abc
//------
//i : 2
//start : 8
//end : 11
//group : xyz

default int end (String name)

Returns the offset after the last character of the subsequence captured by the given named-capturing group during the previous match operation.

final var pattern = Pattern.compile("(?<A>abc|efg)_012_(?<B>x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();
System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

{
    final var name = "A";

    System.out.println(matchResult.start(name)); // 0
    System.out.println(matchResult.end(name)); // 3
    System.out.println(matchResult.group(name)); // "abc"
}

{
    final var name = "B";

    System.out.println(matchResult.start(name)); // 8
    System.out.println(matchResult.end(name)); // 11
    System.out.println(matchResult.group(name)); // "xyz"
}

String group ()

Returns the input subsequence matched by the previous match.

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc");

System.out.println(matcher.lookingAt()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 3
System.out.println(matchResult.group()); // "abc"

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc 345");

final var stream = matcher.results();

stream.forEach(matchResult -> {

    System.out.println("------");
    System.out.println("start : " + matchResult.start());
    System.out.println("end : " + matchResult.end());
    System.out.println("group : " + matchResult.group());
});

// Result
// ↓
//------
//start : 0
//end : 3
//group : abc
//------
//start : 8
//end : 14
//group : aaaabc

String group (int group)

Returns the input subsequence captured by the given group during the previous match operation.

final var pattern = Pattern.compile("(abc|efg)_012_(x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

final var groupCount = matchResult.groupCount();
System.out.println(groupCount); // 2

for (int i = 1; i <= groupCount; i++) {

    System.out.println("------");
    System.out.println("i : " + i);
    System.out.println("start : " + matchResult.start(i));
    System.out.println("end : " + matchResult.end(i));
    System.out.println("group : " + matchResult.group(i));
}

// Result
// ↓
//------
//i : 1
//start : 0
//end : 3
//group : abc
//------
//i : 2
//start : 8
//end : 11
//group : xyz

default String group (String name)

Returns the input subsequence captured by the given named-capturing group during the previous match operation.

final var pattern = Pattern.compile("(?<A>abc|efg)_012_(?<B>x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();
System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

{
    final var name = "A";

    System.out.println(matchResult.start(name)); // 0
    System.out.println(matchResult.end(name)); // 3
    System.out.println(matchResult.group(name)); // "abc"
}

{
    final var name = "B";

    System.out.println(matchResult.start(name)); // 8
    System.out.println(matchResult.end(name)); // 11
    System.out.println(matchResult.group(name)); // "xyz"
}

int groupCount ()

Returns the number of capturing groups in this match result's pattern.

final var pattern = Pattern.compile("(abc|efg)_012_(x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

final var groupCount = matchResult.groupCount();
System.out.println(groupCount); // 2

for (int i = 1; i <= groupCount; i++) {

    System.out.println("------");
    System.out.println("i : " + i);
    System.out.println("start : " + matchResult.start(i));
    System.out.println("end : " + matchResult.end(i));
    System.out.println("group : " + matchResult.group(i));
}

// Result
// ↓
//------
//i : 1
//start : 0
//end : 3
//group : abc
//------
//i : 2
//start : 8
//end : 11
//group : xyz

default boolean hasMatch ()

Returns whether this contains a valid match from a previous match or find operation.

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaabc");

{
    System.out.println(matcher.find()); // true

    final var matchResult = matcher.toMatchResult();
    System.out.println(matchResult.hasMatch()); // true
    System.out.println(matchResult.start()); // 0
    System.out.println(matchResult.end()); // 3
    System.out.println(matchResult.group()); // "abc"
}

{
    System.out.println(matcher.find()); // true

    final var matchResult = matcher.toMatchResult();
    System.out.println(matchResult.hasMatch()); // true
    System.out.println(matchResult.start()); // 8
    System.out.println(matchResult.end()); // 13
    System.out.println(matchResult.group()); // "aaabc"
}

{
    System.out.println(matcher.find()); // false

    final var matchResult = matcher.toMatchResult();
    System.out.println(matchResult.hasMatch()); // false
}

default Map<String,Integer> namedGroups ()

Returns an unmodifiable map from capturing group names to group numbers.

final var pattern = Pattern.compile("(?<A>abc|efg)_012_(?<B>x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true
final var matchResult = matcher.toMatchResult();

System.out.println("-- groups --");
for (final var entry : matchResult.namedGroups().entrySet()) {
    System.out.println("entry : " + entry);

    final var num = entry.getValue();
    System.out.println("  group : " + matchResult.group(num));
}

// Result
// ↓
//true
//-- groups --
//entry : A=1
//  group : abc
//entry : B=2
//  group : xyz

int start ()

Returns the start index of the match.

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc");

System.out.println(matcher.lookingAt()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 3
System.out.println(matchResult.group()); // "abc"

final var pattern = Pattern.compile("a+bc");
final var matcher = pattern.matcher("abc 012 aaaabc 345");

final var stream = matcher.results();

stream.forEach(matchResult -> {

    System.out.println("------");
    System.out.println("start : " + matchResult.start());
    System.out.println("end : " + matchResult.end());
    System.out.println("group : " + matchResult.group());
});

// Result
// ↓
//------
//start : 0
//end : 3
//group : abc
//------
//start : 8
//end : 14
//group : aaaabc

int start (int group)

Returns the start index of the subsequence captured by the given group during this match.

final var pattern = Pattern.compile("(abc|efg)_012_(x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();

System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

final var groupCount = matchResult.groupCount();
System.out.println(groupCount); // 2

for (int i = 1; i <= groupCount; i++) {

    System.out.println("------");
    System.out.println("i : " + i);
    System.out.println("start : " + matchResult.start(i));
    System.out.println("end : " + matchResult.end(i));
    System.out.println("group : " + matchResult.group(i));
}

// Result
// ↓
//------
//i : 1
//start : 0
//end : 3
//group : abc
//------
//i : 2
//start : 8
//end : 11
//group : xyz

default int start (String name)

Returns the start index of the subsequence captured by the given named-capturing group during the previous match operation.

final var pattern = Pattern.compile("(?<A>abc|efg)_012_(?<B>x..)");
final var matcher = pattern.matcher("abc_012_xyz");

System.out.println(matcher.matches()); // true

final var matchResult = matcher.toMatchResult();
System.out.println(matchResult.start()); // 0
System.out.println(matchResult.end()); // 11
System.out.println(matchResult.group()); // "abc_012_xyz"

{
    final var name = "A";

    System.out.println(matchResult.start(name)); // 0
    System.out.println(matchResult.end(name)); // 3
    System.out.println(matchResult.group(name)); // "abc"
}

{
    final var name = "B";

    System.out.println(matchResult.start(name)); // 8
    System.out.println(matchResult.end(name)); // 11
    System.out.println(matchResult.group(name)); // "xyz"
}

API Examples

Java : MatchResult (regex) with Examples

Summary

Methods

int end ()

int end (int group)

default int end (String name)

String group ()

String group (int group)

default String group (String name)

int groupCount ()

default boolean hasMatch ()

default Map<String,Integer> namedGroups ()

int start ()

int start (int group)

default int start (String name)

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