- Qt 6.9
- Qt Core
- C++ Classes
- QRegularExpressionMatch
- Qt 6.9.3 Reference Documentation

# QRegularExpressionMatch Class

The QRegularExpressionMatch class provides the results of a matching a QRegularExpression against a string. More...

Header: | `#include <QRegularExpressionMatch>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Core)` `target_link_libraries(mytarget PRIVATE Qt6::Core)`
qmake: | `QT += core`

- List of all members, including inherited members
- QRegularExpressionMatch is part of Implicitly Shared Classes and Classes for string data.

Note: All functions in this class are reentrant.

## Public Functions

| QRegularExpressionMatch()
| QRegularExpressionMatch(const QRegularExpressionMatch &match)
`(since 6.1)` | QRegularExpressionMatch(QRegularExpressionMatch &&match)
| ~QRegularExpressionMatch()
QString | captured(QAnyStringView name) const
QString | captured(int nth = 0) const
qsizetype | capturedEnd(QAnyStringView name) const
qsizetype | capturedEnd(int nth = 0) const
qsizetype | capturedLength(QAnyStringView name) const
qsizetype | capturedLength(int nth = 0) const
qsizetype | capturedStart(QAnyStringView name) const
qsizetype | capturedStart(int nth = 0) const
QStringList | capturedTexts() const
QStringView | capturedView(QAnyStringView name) const
QStringView | capturedView(int nth = 0) const
`(since 6.3)` bool | hasCaptured(QAnyStringView name) const
`(since 6.3)` bool | hasCaptured(int nth) const
bool | hasMatch() const
bool | hasPartialMatch() const
bool | isValid() const
int | lastCapturedIndex() const
QRegularExpression::MatchOptions | matchOptions() const
QRegularExpression::MatchType | matchType() const
QRegularExpression | regularExpression() const
void | swap(QRegularExpressionMatch &other)
QRegularExpressionMatch & | operator=(QRegularExpressionMatch &&match)
QRegularExpressionMatch & | operator=(const QRegularExpressionMatch &match)

## Related Non-Members

QDebug | operator<<(QDebug debug, const QRegularExpressionMatch &match)

## Detailed Description

A QRegularExpressionMatch object can be obtained by calling the QRegularExpression::match() function, or as a single result of a global match from a QRegularExpressionMatchIterator.

The success or the failure of a match attempt can be inspected by calling the hasMatch() function. QRegularExpressionMatch also reports a successful partial match through the hasPartialMatch() function.

In addition, QRegularExpressionMatch returns the substrings captured by the capturing groups in the pattern string. The implicit capturing group with index 0 captures the result of the whole match. The captured() function returns each substring captured, either by the capturing group's index or by its name:

     QRegularExpression re("(\\d\\d) (?<name>\\w+)");
     QRegularExpressionMatch match = re.match("23 Jordan");
     if (match.hasMatch()) {
         QString number = match.captured(1); // first == "23"
         QString name = match.captured("name"); // name == "Jordan"
     }

For each captured substring it is possible to query its starting and ending offsets in the subject string by calling the capturedStart() and the capturedEnd() function, respectively. The length of each captured substring is available using the capturedLength() function.

The convenience function capturedTexts() will return all the captured substrings at once (including the substring matched by the entire pattern) in the order they have been captured by capturing groups; that is, `captured(i) == capturedTexts().at(i)`.

You can retrieve the QRegularExpression object the subject string was matched against by calling the regularExpression() function; the match type and the match options are available as well by calling the matchType() and the matchOptions() respectively.

Please refer to the QRegularExpression documentation for more information about the Qt regular expression classes.

See also QRegularExpression.

## Member Function Documentation

### QRegularExpressionMatch::QRegularExpressionMatch()

Constructs a valid, empty QRegularExpressionMatch object. The regular expression is set to a default-constructed one; the match type to QRegularExpression::NoMatch and the match options to QRegularExpression::NoMatchOption.

The object will report no match through the hasMatch() and the hasPartialMatch() member functions.

### QRegularExpressionMatch::QRegularExpressionMatch(const QRegularExpressionMatch &match)

Constructs a match result by copying the result of the given match.

See also operator=().

### `[noexcept, since 6.1]` QRegularExpressionMatch::QRegularExpressionMatch(QRegularExpressionMatch &&match)

Constructs a match result by moving the result from the given match.

Note that a moved-from QRegularExpressionMatch can only be destroyed or assigned to. The effect of calling other functions than the destructor or one of the assignment operators is undefined.

This function was introduced in Qt 6.1.

See also operator=().

### `[noexcept]` QRegularExpressionMatch::~QRegularExpressionMatch()

Destroys the match result.

### QString QRegularExpressionMatch::captured(QAnyStringView name) const

Returns the substring captured by the capturing group named name.

If the named capturing group name did not capture a string, or if there is no capturing group named name, returns a null QString.

Note: In Qt versions prior to 6.8, this function took QString or QStringView, not QAnyStringView.

See also capturedView(), capturedStart(), capturedEnd(), capturedLength(), and QString::isNull().

### QString QRegularExpressionMatch::captured(int nth = 0) const

Returns the substring captured by the nth capturing group.

If the nth capturing group did not capture a string, or if there is no such capturing group, returns a null QString.

Note: The implicit capturing group number 0 captures the substring matched by the entire pattern.

See also capturedView(), lastCapturedIndex(), capturedStart(), capturedEnd(), capturedLength(), and QString::isNull().

### qsizetype QRegularExpressionMatch::capturedEnd(QAnyStringView name) const

Returns the offset inside the subject string immediately after the ending position of the substring captured by the capturing group named name. If the capturing group named name did not capture a string or doesn't exist, returns -1.

Note: In Qt versions prior to 6.8, this function took QString or QStringView, not QAnyStringView.

See also capturedStart(), capturedLength(), and captured().

### qsizetype QRegularExpressionMatch::capturedEnd(int nth = 0) const

Returns the offset inside the subject string immediately after the ending position of the substring captured by the nth capturing group. If the nth capturing group did not capture a string or doesn't exist, returns -1.

See also capturedStart(), capturedLength(), and captured().

### qsizetype QRegularExpressionMatch::capturedLength(QAnyStringView name) const

Returns the length of the substring captured by the capturing group named name.

Note: This function returns 0 if the capturing group named name did not capture a string or doesn't exist.

Note: In Qt versions prior to 6.8, this function took QString or QStringView, not QAnyStringView.

See also capturedStart(), capturedEnd(), and captured().

### qsizetype QRegularExpressionMatch::capturedLength(int nth = 0) const

Returns the length of the substring captured by the nth capturing group.

Note: This function returns 0 if the nth capturing group did not capture a string or doesn't exist.

See also capturedStart(), capturedEnd(), and captured().

### qsizetype QRegularExpressionMatch::capturedStart(QAnyStringView name) const

Returns the offset inside the subject string corresponding to the starting position of the substring captured by the capturing group named name. If the capturing group named name did not capture a string or doesn't exist, returns -1.

Note: In Qt versions prior to 6.8, this function took QString or QStringView, not QAnyStringView.

See also capturedEnd(), capturedLength(), and captured().

### qsizetype QRegularExpressionMatch::capturedStart(int nth = 0) const

Returns the offset inside the subject string corresponding to the starting position of the substring captured by the nth capturing group. If the nth capturing group did not capture a string or doesn't exist, returns -1.

See also capturedEnd(), capturedLength(), and captured().

### QStringList QRegularExpressionMatch::capturedTexts() const

Returns a list of all strings captured by capturing groups, in the order the groups themselves appear in the pattern string. The list includes the implicit capturing group number 0, capturing the substring matched by the entire pattern.

### QStringView QRegularExpressionMatch::capturedView(QAnyStringView name) const

Returns a view of the string captured by the capturing group named name.

If the named capturing group name did not capture a string, or if there is no capturing group named name, returns a null QStringView.

Note: In Qt versions prior to 6.8, this function took QString or QStringView, not QAnyStringView.

See also captured(), capturedStart(), capturedEnd(), capturedLength(), and QStringView::isNull().

### QStringView QRegularExpressionMatch::capturedView(int nth = 0) const

Returns a view of the substring captured by the nth capturing group.

If the nth capturing group did not capture a string, or if there is no such capturing group, returns a null QStringView.

Note: The implicit capturing group number 0 captures the substring matched by the entire pattern.

See also captured(), lastCapturedIndex(), capturedStart(), capturedEnd(), capturedLength(), and QStringView::isNull().

### `[since 6.3]` bool QRegularExpressionMatch::hasCaptured(QAnyStringView name) const

Returns true if the capturing group named name captured something in the subject string, and false otherwise (or if there is no capturing group called name).

Note: Some capturing groups in a regular expression may not have captured anything even if the regular expression matched. This may happen, for instance, if a conditional operator is used in the pattern:

     QRegularExpression re("([a-z]+)|([A-Z]+)");
     QRegularExpressionMatch m = re.match("UPPERCASE");
     if (m.hasMatch()) {
         qDebug() << m.hasCaptured(0); // true
         qDebug() << m.hasCaptured(1); // false
         qDebug() << m.hasCaptured(2); // true
     }

Similarly, a capturing group may capture a substring of length 0; this function will return `true` for such a capturing group.

Note: In Qt versions prior to 6.8, this function took QString or QStringView, not QAnyStringView.

This function was introduced in Qt 6.3.

See also captured() and hasMatch().

### `[since 6.3]` bool QRegularExpressionMatch::hasCaptured(int nth) const

Returns true if the nth capturing group captured something in the subject string, and false otherwise (or if there is no such capturing group).

Note: The implicit capturing group number 0 captures the substring matched by the entire pattern.

Note: Some capturing groups in a regular expression may not have captured anything even if the regular expression matched. This may happen, for instance, if a conditional operator is used in the pattern:

     QRegularExpression re("([a-z]+)|([A-Z]+)");
     QRegularExpressionMatch m = re.match("UPPERCASE");
     if (m.hasMatch()) {
         qDebug() << m.hasCaptured(0); // true
         qDebug() << m.hasCaptured(1); // false
         qDebug() << m.hasCaptured(2); // true
     }

Similarly, a capturing group may capture a substring of length 0; this function will return `true` for such a capturing group.

This function was introduced in Qt 6.3.

See also captured(), lastCapturedIndex(), and hasMatch().

### bool QRegularExpressionMatch::hasMatch() const

Returns `true` if the regular expression matched against the subject string, or false otherwise.

See also QRegularExpression::match() and hasPartialMatch().

### bool QRegularExpressionMatch::hasPartialMatch() const

Returns `true` if the regular expression partially matched against the subject string, or false otherwise.

Note: Only a match that explicitly used the one of the partial match types can yield a partial match. Still, if such a match succeeds totally, this function will return false, while hasMatch() will return true.

See also QRegularExpression::match(), QRegularExpression::MatchType, and hasMatch().

### bool QRegularExpressionMatch::isValid() const

Returns `true` if the match object was obtained as a result from the QRegularExpression::match() function invoked on a valid QRegularExpression object; returns `false` if the QRegularExpression was invalid.

See also QRegularExpression::match() and QRegularExpression::isValid().

### int QRegularExpressionMatch::lastCapturedIndex() const

Returns the index of the last capturing group that captured something, including the implicit capturing group 0. This can be used to extract all the substrings that were captured:

     QRegularExpressionMatch match = re.match(string);
     for (int i = 0; i <= match.lastCapturedIndex(); ++i) {
         QString captured = match.captured(i);
         // ...
     }

Note that some of the capturing groups with an index less than lastCapturedIndex() could have not matched, and therefore captured nothing.

If the regular expression did not match, this function returns -1.

See also hasCaptured(), captured(), capturedStart(), capturedEnd(), and capturedLength().

### QRegularExpression::MatchOptions QRegularExpressionMatch::matchOptions() const

Returns the match options that were used to get this QRegularExpressionMatch object, that is, the match options that were passed to QRegularExpression::match() or QRegularExpression::globalMatch().

See also QRegularExpression::match(), regularExpression(), and matchType().

### QRegularExpression::MatchType QRegularExpressionMatch::matchType() const

Returns the match type that was used to get this QRegularExpressionMatch object, that is, the match type that was passed to QRegularExpression::match() or QRegularExpression::globalMatch().

See also QRegularExpression::match(), regularExpression(), and matchOptions().

### QRegularExpression QRegularExpressionMatch::regularExpression() const

Returns the QRegularExpression object whose match() function returned this object.

See also QRegularExpression::match(), matchType(), and matchOptions().

### `[noexcept]` void QRegularExpressionMatch::swap(QRegularExpressionMatch &other)

Swaps this match result with other. This operation is very fast and never fails.

### `[noexcept]` QRegularExpressionMatch &QRegularExpressionMatch::operator=(QRegularExpressionMatch &&match)

Move-assigns the match result match to this object, and returns a reference to the result.

Note that a moved-from QRegularExpressionMatch can only be destroyed or assigned to. The effect of calling other functions than the destructor or one of the assignment operators is undefined.

### QRegularExpressionMatch &QRegularExpressionMatch::operator=(const QRegularExpressionMatch &match)

Assigns the match result match to this object, and returns a reference to the copy.

## Related Non-Members

### QDebug operator<<(QDebug debug, const QRegularExpressionMatch &match)

Writes the match object match into the debug object debug for debugging purposes.

See also Debugging Techniques.