QT中字符串的比較、查找、替換等操作

基本操作

    QString s1 = "Welcome";
    QString s2;
    s2 = s1 + "to you";
    QString s3 = "Hello ";
    s3 = s3 + "World";
    qDebug() << s2 << endl << s3 << endl;
    QString s4 = "Hello";
    s4.append( " World");
    qDebug() << s4 << endl;
    QString s5;
    s5.sprintf("%s","Welcome to my world");
    qDebug() << s5 << endl;
    QString s6;
    s6 = QString("I'm %1 %2").arg("is").arg("Marco");
    qDebug() << s6 << endl;

插入

    //任意位置
    QString s7("Marco  good");
    s7.insert(6,"is");
    qDebug() << s7 << endl;
    //開頭
    QString s8(" is good");
    s8.prepend("Marco");
    qDebug() << s8 << endl;

替換

    QString s9("Marco is bad");
    s9.replace("bad","good");
    qDebug() << s9 << endl;

移除字符串兩端空白

    QString s10("      Marco is good    ");
    s10 = s10.trimmed();
    qDebug() << s10 << endl;

移除字符串兩端空白並添加一個空白符

    QString s11("      Marco is good    ");
    s11 = s11.simplified();
    qDebug() << s11 << endl;

查詢字符串內容

    //查詢字符串開頭
    QString s12("Welcome to you");
    qDebug() << s12.startsWith("Welcome",Qt::CaseSensitive) << " "
             << s12.startsWith("welcome",Qt::CaseInsensitive) << endl;//true
    //查詢字符串結尾
    qDebug() << s12.endsWith("you",Qt::CaseSensitive) << " "
             << s12.endsWith("You",Qt::CaseInsensitive) << endl;//true
    //遍歷整個字符串判斷內容是否出現過
    qDebug() << s12.contains("to",Qt::CaseSensitive) << " "
             << s12.contains("To",Qt::CaseInsensitive) << endl;

比較

    //localeAwareCompare(const QString& ,const QString &)靜態成員函數
    //比較兩個字符串如果前者小於後者返回負整值，等於返回0，大於返回正整數
    if(QString::localeAwareCompare(s11,s12) < 0)
        qDebug() << "s11 < s12" << endl;
    else if(QString::localeAwareCompare(s11,s12) > 0)
        qDebug() << "s11 > s12" << endl;
    else if(QString::localeAwareCompare(s11,s12) == 0)
        qDebug() << "s11 == s12" << endl;
    //compare()//該函數可指定是否區分大小寫比較，其他跟localeAwareCompare()類似
    if(QString::compare(s11,s12,Qt::CaseSensitive) < 0)
        qDebug() << "s11 < s12" << endl;
    else if(QString::compare(s11,s12,Qt::CaseSensitive) > 0)
        qDebug() << "s11 > s12" << endl;
    else if(QString::compare(s11,s12,Qt::CaseSensitive) == 0)
        qDebug() << "s11 == s12" << endl;