How can I extract numerical values from a string in Qt?

In Qt, you can use some built-in methods of QRegExp, QStringList, or QString to extract numbers from a string.

1. Use QRegExp:

QString text = "Hello123World456";
QRegExp regex("\\d+");  // 匹配一个或多个数字
int pos = 0;
while ((pos = regex.indexIn(text, pos)) != -1) {
    QString number = regex.cap(0);  // 获取匹配到的数字
    // 处理数字
    qDebug() << number;
    pos += regex.matchedLength();
}

1. Utilize QStringList:

QString text = "Hello 123 World 456";
QStringList list = text.split(QRegExp("\\D+"));  // 使用非数字字符分割字符串
foreach (const QString &number, list) {
    if (!number.isEmpty()) {
        // 处理数字
        qDebug() << number;
    }
}

1. Utilizing the toInt() or toDouble() method in QString:

QString text = "Hello 123 World 456";
QString number;
int pos = 0;
while (pos < text.length()) {
    if (text[pos].isDigit()) {  // 找到数字的起始位置
        int startPos = pos;
        while (pos < text.length() && text[pos].isDigit()) {
            pos++;
        }
        number = text.mid(startPos, pos - startPos);  // 截取数字
        // 处理数字
        qDebug() << number;
    }
    pos++;
}

Please choose the method that best suits your actual needs.