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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>. Like QList, QStringList is implicitly shared. It provides fast index-based access as well as fast insertions and removals. Passing string lists as value parameters is both fast and safe.
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(), removeAll(), removeAt(), removeFirst(), removeLast(), and removeOne() to modify a QStringList. In addition, QStringList provides a few convenience functions that make handling lists of strings easier:
Strings can be added to a list using the append(), operator+=() and operator<<() functions. For example:
QStringList fonts;
fonts << "Arial" << "Helvetica" << "Times" << "Courier";
To iterate over a list, you can either use index positions or QList's Java-style and STL-style iterator types:
Indexing:
for (int i = 0; i < fonts.size(); ++i)
cout << fonts.at(i).toLocal8Bit().constData() << endl;
Java-style iterator:
QStringListIterator javaStyleIterator(fonts);
while (javaStyleIterator.hasNext())
cout << javaStyleIterator.next().toLocal8Bit().constData() << endl;
STL-style iterator:
QStringList.const_iterator constIterator;
for (constIterator = fonts.constBegin(); constIterator != fonts.constEnd();
++constIterator)
cout << (*constIterator).toLocal8Bit().constData() << endl;
The QStringListIterator class is simply a type definition for QListIterator<QString>. QStringList also provide the QMutableStringListIterator class which is a type definition for QMutableListIterator<QString>.
QStringList provides several functions allowing you to manipulate the contents of a list. You can concatenate all the strings in a string list into a single string (with an optional separator) using the join() function. For example:
QString str = fonts.join(",");
// str == "Arial,Helvetica,Times,Courier"
To break up a string into a string list, use the QString.split() function:
QStringList list;
list = str.split(",");
// list: ["Arial", "Helvetica", "Times", "Courier"]
The argument to split can be a single character, a string, or a QRegExp.
In addition, the operator+() function allows you to concatenate two string lists into one. To sort a string list, use the sort() function.
QString list also provides the filter() function which lets you to extract a new list which contains only those strings which contain a particular substring (or match a particular regular expression):
QStringList monospacedFonts = fonts.filter(QRegExp("Courier|Fixed"));
The contains() function tells you whether the list contains a given string, while the indexOf() function returns the index of the first occurrence of the given string. The lastIndexOf() function on the other hand, returns the index of the last occurrence of the string.
Finally, the replaceInStrings() function calls QString.replace() on each string in the string list in turn. For example:
QStringList files;
files << "$QTDIR/src/moc/moc.y"
<< "$QTDIR/src/moc/moc.l"
<< "$QTDIR/include/qconfig.h";
files.replaceInStrings("$QTDIR", "/usr/lib/qt");
// files: [ "/usr/lib/qt/src/moc/moc.y", ...]
Constructs an empty string list.
Constructs a string list that contains the given string, str. Longer lists are easily created like this:
QStringList longerList = (QStringList() << str1 << str2 << str3);
See also append().
Constructs a copy of the other string list.
This operation takes constant time because QStringList is implicitly shared, making the process of 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. The search is case insensitive if cs is Qt.CaseInsensitive; the search is case sensitive by default.
See also indexOf(), lastIndexOf(), and QString.contains().
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;
result = list.filter("Bill");
// result: ["Bill Murray", "Bill Clinton"]
This is equivalent to
QStringList result;
foreach (const QString &str, list) {
if (str.contains("Bill"))
result += str;
}
See also contains().
This is an overloaded function.
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.
By default, this function is case sensitive.
See also lastIndexOf(), contains(), and QRegExp.exactMatch().
Returns the index position of the first occurrence of value in the list, searching forward from index position from. Returns -1 if no item matched.
See also lastIndexOf(), contains(), and QList.indexOf().
Joins all the string list's strings into a single string with each element separated by the given separator (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.
By default, this function is case sensitive.
See also indexOf(), contains(), and QRegExp.exactMatch().
Returns the index position of the last occurrence of value 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.
By default, this function is case sensitive.
See also indexOf() and QList.lastIndexOf().
This function removes duplicate entries from a list. The entries do not have to be sorted. They will retain their original order.
Returns the number of removed entries.
This function was introduced in Qt 4.5.
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.
For example:
QStringList list;
list << "alpha" << "beta" << "gamma" << "epsilon";
list.replaceInStrings("a", "o");
// list == ["olpho", "beto", "gommo", "epsilon"]
See also QString.replace().
This is an overloaded function.
Replaces every occurrence of the regexp rx, in each of the string lists's strings, with after. Returns a reference to the string list.
For example:
QStringList list;
list << "alpha" << "beta" << "gamma" << "epsilon";
list.replaceInStrings(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), ...
For example:
QStringList list;
list << "Bill Clinton" << "Murray, Bill";
list.replaceInStrings(QRegExp("^(.*), (.*)$"), "\\2 \\1");
// list == ["Bill Clinton", "Bill Murray"]
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 the QMap class. 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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