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QRegExp Class Reference


The QRegExp class provides pattern matching using regular expressions or wildcards. More...

#include <qregexp.h>

List of all member functions.

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Protected Members


Detailed Description

The QRegExp class provides pattern matching using regular expressions or wildcards.

QRegExp knows these regexp primitives:

In wildcard mode, it only knows four primitives:

QRegExp supports Unicode both in the pattern strings and in the strings to be matched.

When writing regular expressions in C++ code, remember that C++ processes \ characters. So in order to match e.g. a "." character, you must write "\\." in C++ source, not "\.".

A character set matches a defined set of characters. For example, [BSD] matches any of 'B', 'D' and 'S'. Within a character set, the special characters '.', '*', '?', '^', '$', '+' and '[' lose their special meanings. The following special characters apply:

Thus, [a-zA-Z0-9.] matches upper and lower case ASCII letters, digits and dot; and [^\s] matches everything except white space.

\note In Qt 3.0, the language of regular expressions will contain five more special characters, namely '(', ')', '{', '|' and '}'. To ease porting, it's a good idea to escape these characters with a backslash in all the regular expressions you'll write from now on.

Bugs and limitations:

Examples: qmag/qmag.cpp


Member Function Documentation

QRegExp::QRegExp ()

Constructs an empty regular expression.

QRegExp::QRegExp ( const QString & pattern, bool caseSensitive=TRUE, bool wildcard=FALSE )

Constructs a regular expression.

Arguments:

See also setWildcard().

QRegExp::QRegExp ( const QRegExp & r )

Constructs a regular expression which is a copy of r.

See also operator=(const and QRegExp&).

QRegExp::~QRegExp ()

Destructs the regular expression and cleans up its internal data.

bool QRegExp::caseSensitive () const

Returns TRUE if case sensitivity is enabled, otherwise FALSE. The default is TRUE.

See also setCaseSensitive().

int QRegExp::find ( const QString & str, int index )

Attempts to match in str, starting from position index. Returns the position of the match, or -1 if there was no match.

See also match().

bool QRegExp::isEmpty () const

Returns TRUE if the regexp is empty.

bool QRegExp::isValid () const

Returns TRUE if the regexp is valid, or FALSE if it is invalid.

The pattern "[a-z" is an example of an invalid pattern, since it lacks a closing bracket.

int QRegExp::match ( const QString & str, int index=0, int * len=0, bool indexIsStart = TRUE ) const

Attempts to match in str, starting from position index. Returns the position of the match, or -1 if there was no match.

If len is not a null pointer, the length of the match is stored in *len.

If indexIsStart is TRUE (the default), the position index in the string will match the start-of-input primitive (^) in the regexp, if present. Otherwise, position 0 in str will match.

Example:

    QRegExp r("[0-9]*\\.[0-9]+");               // matches floating point
    int len;
    r.match("pi = 3.1416", 0, &len);            // returns 5, len == 6

\note In Qt 3.0, this function will be replaced by find().

Examples: qmag/qmag.cpp

bool QRegExp::operator!= ( const QRegExp & r ) const

Returns TRUE if this regexp is not equal to r.

See also operator==().

QRegExp & QRegExp::operator= ( const QString & pattern )

This function is obsolete. It is provided to keep old source working, and will probably be removed in a future version of Qt. We strongly advise against using it in new code.

Consider using setPattern() instead of this method.

Sets the pattern string to pattern and returns a reference to this regexp. The case sensitivity or wildcard options do not change.

QRegExp & QRegExp::operator= ( const QRegExp & r )

Copies the regexp r and returns a reference to this regexp. The case sensitivity and wildcard options are copied, as well.

bool QRegExp::operator== ( const QRegExp & r ) const

Returns TRUE if this regexp is equal to r.

Two regexp objects are equal if they have equal pattern strings, case sensitivity options and wildcard options.

QString QRegExp::pattern () const

Returns the pattern string of the regexp.

void QRegExp::setCaseSensitive ( bool enable )

Enables or disables case sensitive matching.

In case sensitive mode, "a.e" matches "axe" but not "Axe".

See also: caseSensitive().

void QRegExp::setPattern ( const QString & pattern )

Sets the pattern string to pattern and returns a reference to this regexp. The case sensitivity or wildcard options do not change.

void QRegExp::setWildcard ( bool wildcard )

Sets the wildcard option for the regular expression. The default is FALSE.

Setting wildcard to TRUE makes it convenient to match filenames instead of plain text.

For example, "qr*.cpp" matches the string "qregexp.cpp" in wildcard mode, but not "qicpp" (which would be matched in normal mode).

See also wildcard().

bool QRegExp::wildcard () const

Returns TRUE if wildcard mode is on, otherwise FALSE.

See also setWildcard().

void QRegExp::compile () [protected]

For internal use only.

const QChar * QRegExp::matchstr ( uint * rxd, const QChar * str, uint strlength, const QChar * bol ) const [protected]

For internal use only.


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