QString的不常见用法

QString str("Hello");

QString str = "Hello";

static const QChar data[4] = { 0x0055, 0x006e, 0x10e3, 0x03a3 };

QString str(data, 4);

QString str;

str.resize(4);

str[0] = QChar('U');

str[1] = QChar('n');

str[2] = QChar(0x10e3);

str[3] = QChar(0x03a3);

QString str;

str.sprintf("%s %.3f", "float", 3.1415926);

//str结果是"float 3.14"

QString str;

str.setNum(10); //str = "10"

str.setNum(10, 16); //str = "a"

str.setNum(10.12345); //str = "10.12345"

QString i; // current file's number

QString total; // number of files to process

QString fileName; // current file's name

QString status = QString("Processing file %1 of %2: %3")

.arg(i).arg(total).arg(fileName);

1)Char * 初始化

QString str = "Hello";

QString converts the const char * data into Unicode using the fromAscii() function.

2)QChar[]数组初始化

Cpp代码

1. 1. 
      
2. static const QChar data[4] = { 0x0055, 0x006e, 0x10e3, 0x03a3 };
3. QString str(data, 4);
   1. 
      

也可以这样

Cpp代码

1. 1. 
      
2. QRegExp pattern;
3. static const QChar unicode[] = { 0x005A, 0x007F, 0x00A4, 0x0060,
4. 0x1009, 0x0020, 0x0020};
5. int size = sizeof(unicode) / sizeof(QChar);
6. QString str = QString::fromRawData(unicode, size);
   1. 
      

3)还可以通过risize()函数和每个QChar字符进行初始化

Cpp代码

1. 1. 
      
2. QString str;
3. str.resize(4);
4. 
   
5. str[0] = QChar('U');
6. str[1] = QChar('n');
7. str[2] = QChar(0x10e3);
8. str[3] = QChar(0x03a3);
   1. 
      

通过at()函数进行每个字符读取

Cpp代码

1. 1. 
      
2. QString str;
3. 
   
4. for (int i = 0; i < str.size(); ++i) {
5. if (str.at(i) >= QChar('a') && str.at(i) <= QChar('f'))
6. qDebug() << "Found character in range [a-f]";
7. }