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The QStringList class provides a list of strings. More...
A Python list of Python string or unicode objects or QString instances may be used whenever a QStringList is expected.
The QStringList class provides a list of strings.
QStringList inherits from QList<QString>. All of QList's functionality also applies to QStringList. For example, you can use isEmpty() to test whether the list is empty, and you can call functions like append(), prepend(), insert(), replace(), and remove() to modify a QStringList. In addition, QStringList provides a few convenience functions that make handling lists of strings easier.
Like QList, QStringList is implicitly shared. QStringList provides fast index-based access as well as fast insertions and removals. Passing string lists as value parameters is both fast and safe.
Strings can be added to a list using append(), operator+=(), or operator<<(). For example:
QStringList fonts;
fonts << "Arial" << "Helvetica" << "Times" << "Courier";
To iterate over a string, you can either use index positions or QList's Java-style and STL-style iterator types. Here are examples of each approach.
Indexing:
for (int i = 0; i < fonts.size(); ++i)
cout << fonts.at(i).toLocal8Bit().constData() << endl;
Java-style iterator:
QStringListIterator i(fonts);
while (i.hasNext())
cout << i.next().toLocal8Bit().constData() << endl;
STL-style iterator:
QStringList.const_iterator i;
for (i = fonts.constBegin(); i != fonts.constEnd(); ++i)
cout << (*i).toLocal8Bit().constData() << endl;
QStringListIterator and QMutableStringListIterator are simply typedefs for QListIterator<QString> and QMutableListIterator<QString>.
You can concatenate all the strings in a string list into a single string (with an optional separator) using join(). For example:
QString str = fonts.join(",");
// str == "Arial,Helvetica,Times,Courier"
To break up a string into a string list, use QString.split():
QString str = "Arial,Helvetica,Times,Courier";
QStringList list = str.split(",");
// list: ["Arial", "Helvetica", "Times", "Courier"]
The argument to split can be a single character, a string, or a QRegExp.
You can sort a string list with sort(), and extract a new list which contains only those strings which contain a particular substring (or match a particular regular expression) using the find() functions. For example:
QStringList monospacedFonts = fonts.find(QRegExp("Courier|Fixed"));
Similarly, the replace() function calls QString.replace() on each string in the string list in turn. Here's an example that uses it to replace all occurrences of "$QTDIR" with "/usr/lib/qt" in a string list:
QStringList files;
files << "$QTDIR/src/moc/moc.y"
<< "$QTDIR/src/moc/moc.l"
<< "$QTDIR/include/qconfig.h";
files.replace("$QTDIR", "/usr/lib/qt");
See also QString, QStringListIterator, and QMutableStringListIterator.
Constructs an empty string list.
Constructs a string list that contains one string, str. Longer lists are easily created like this:
list = (QStringList() << str1 << str2 << str3);
Constructs a copy of other.
This operation takes constant time, because QStringList is implicitly shared. This makes returning a QStringList from a function very fast. If a shared instance is modified, it will be copied (copy-on-write), and that takes linear time.
See also operator=().
Returns true if the list contains the string str; otherwise returns false. Does a case insensitive search if cs is Qt.CaseInsensitive; by default, the search is case sensitive.
Returns a list of all the strings containing the substring str.
If cs is Qt.CaseSensitive (the default), the string comparison is case sensitive; otherwise the comparison is case insensitive.
QStringList list;
list << "Bill Murray" << "John Doe" << "Bill Clinton";
QStringList result = list.filter("Bill");
// result: ["Bill Murray", "Bill Clinton"]
This is equivalent to
QStringList result;
foreach (QString str, list) {
if (str.contains("Bill"))
result += str;
}
See also QString.contains().
This is an overloaded member function, provided for convenience.
Returns a list of all the strings that match the regular expression rx.
Returns the index position of the first exact match of rx in the list, searching forward from index position from. Returns -1 if no item matched.
See also lastIndexOf() and QRegExp.exactMatch().
Joins the all the string list's strings into a single string with each element separated by the string sep (which can be an empty string).
See also QString.split().
Returns the index position of the last exact match of rx in the list, searching backward from index position from. If from is -1 (the default), the search starts at the last item. Returns -1 if no item matched.
See also indexOf() and QRegExp.exactMatch().
Returns a string list where every string has had the before text replaced with the after text wherever the before text is found. The before text is matched case-sensitively or not depending on the cs flag.
Example:
QStringList list;
list << "alpha" << "beta" << "gamma" << "epsilon";
list.replace("a", "o");
// list == ["olpho", "beto", "gommo", "epsilon"]
See also QString.replace().
This is an overloaded member function, provided for convenience.
Replaces every occurrence of the regexp rx, in each of the string lists's strings, with after. Returns a reference to the string list.
Example:
QStringList list;
list << "alpha" << "beta" << "gamma" << "epsilon";
list.replace(QRegExp("^a"), "o");
// list == ["olpha", "beta", "gamma", "epsilon"]
For regular expressions that contain capturing parentheses, occurrences of \1, \2, ..., in after are replaced with rx.cap(1), rx.cap(2), ...
Example:
QStringList list;
list << "Bill Clinton" << "Murray, Bill";
list.replace(QRegExp("^(.*), (.*)$"), "\\2 \\1");
// list == ["Bill Clinton", "Bill Murray"]
See also replace().
Sorts the list of strings in ascending order (case sensitively).
Sorting is performed using Qt's qSort() algorithm, which operates in linear-logarithmic time, i.e. O(n log n).
If you want to sort your strings in an arbitrary order, consider using a QMap. For example, you could use a QMap<QString, QString> to create a case-insensitive ordering (e.g. with the keys being lower-case versions of the strings, and the values being the strings), or a QMap<int, QString> to sort the strings by some integer index.
See also qSort().
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