1. Containers
QVector, QList, QLinkedList, QMap, QHash, QByteArray, QString and QVariant

2. QVector QVector<double> vector;
vector.insert(1, 3, 9.9);
// vector: [2.718, 9.9, 9.9, 9.9, 1.442, ]
QVector<QString> vector(0);
vector.append("one");
vector.append("two");
vector.append("three");
// vector: ["one", "two", "three"]

3. QVector for (i=0; i<vector.size(); i++) {
qDebug() << vector.at(i);
qDebug() << vector[i]; }

4. QList QList<QString> list;
list << "one" << "two" << "three";
// list: ["one", "two", "three"]
if (list[0] == "one") {
list[0] = "zero"; }
for (int i = 0; i < list.size(); ++i) {
if (list.at(i) == "Jane") {
cout << "Found Jane at " << i << endl;

5. QList STL-Style QList<QString> list;
list << "A" << "B" << "C" << "D";
QList<QString>::iterator i;
for (i = list.begin(); i != list.end(); ++i) {
*i = (*i).toLower(); }

6. QList Java Style QList<QString> list;
list << "A" << "B" << "C" << "D";
QListIterator<QString> i(list);
while (i.hasNext()) {
qDebug() << i.next(); }
QListIterator<QString> j(list);
j.toBack();
while (j.hasPrevious()) {
qDebug() << j.previous();

7. QList Iterator Error QList<QString> list;
list << "A" << "B" << "C" << "D";
QList<QString>::iterator i;
QList<QString>::iterator next;
for (i = list.begin(); i != list.end(); ++i)
next = i+1;
list.erace(i);
qDebug() << *next; }
THIS WILL CRASH!!!

8. Qt Containers object requirements
The values stored in the various containers can be of any assignable data type. To qualify, a type must provide a default constructor, a copy constructor, and an assignment operator.
class Employee {
public:
Employee() {}
Employee(const Employee &other);
Employee &operator=(const Employee &other);
... };

9. foreach QList<QString> list; QString str; foreach (str, list) {
qDebug() << str; }

10. QMap QMap<QString, int> map; map["one"] = 1; map["three"] = 3;
map["seven"] = 7;
...
map.insert("twelve", 12);
int num1 = map["thirteen"]; // insert & return 0
int num2 = map.value("thirteen"); // return 0

11. QMap Iterators QMapIterator<QString, int> i(map);
while (i.hasNext()) {
i.next();
cout << i.key() << ": " << i.value() << endl; }

12. QMultiMap map.insert("plenty", 100); map.insert("plenty", 2000);
// map.value("plenty") == 2000
insertMulti()
QList<int> values = map.values("plenty");
for (int i = 0; i < values.size(); ++i)
cout << values.at(i) << endl;

13. QHash Similar to QMap: - QHash provides faster lookups than QMap.
- When iterating over a QMap, the items are always sorted by key. With QHash, the items are arbitrarily ordered.
- The key type of a QMap must provide operator<(). The key type of a QHash must provide operator==() and a global hash function called qHash()

14. QStringList QStringList is an extended QList<QString>
QStringList tmp;
tmp << “hello” << “Qt” << “World”;
qDebug() << tmp.join(“ “);