QT中字符串的比较、查找、替换等操作_qt字符串替换

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;
    //开头
    QString s8(" is good");
    s8.prepend("Marco");
    qDebug() << s8 << endl;

替换

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

移除字符串两端空白

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

移除字符串两端空白并添加一个空白符

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

查询字符串内容

    //查询字符串开头
    QString s12("Welcome to you");
    qDebug() << s12.startsWith("Welcome",Qt::CaseSensitive) << " "
             << s12.startsWith("welcome",Qt::CaseInsensitive) << endl;//true
    //查询字符串结尾
    qDebug() << s12.endsWith("you",Qt::CaseSensitive) << " "
             << s12.endsWith("You",Qt::CaseInsensitive) << endl;//true
    //遍历整个字符串判断内容是否出现过
    qDebug() << s12.contains("to",Qt::CaseSensitive) << " "
             << s12.contains("To",Qt::CaseInsensitive) << endl;

比较

    //localeAwareCompare(const QString& ,const QString &)静态成员函数
    //比较两个字符串如果前者小于后者返回负整值，等于返回0，大于返回正整数
    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()//该函数可指定是否区分大小写比较，其他跟localeAwareCompare()类似
    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;