在此之前需要配置Qt环境：Qt环境配置

数据转换

QString str1 = "123";
    QString str2 = "456";

    // 数据转换 to int
    int a1 = str1.toInt();
    int a2 = str2.toInt();

    qDebug() << a1+a2;

    // 数字转QString
    int a3 = 520;                               // 208h
    QString str3 = QString::number(a3,16);      // 转为16进制

    qDebug() << str3;

字符串拼接

 // 字符串拼接
    QString str4 = "hello";
    QString str5 = "_";
    QString str6 = "world";

    qDebug() << str4 + str5 + str6;             // "+"被重载了

转换大小写

//转换大小写
    QString str7 = "Qt";
    QString str8 = str7.toLower();
    qDebug() << str8;
    QString str9 = str4.toUpper();
    qDebug() << str9;

获取字符串长度

//判断字符长度： count/size/length
    int len1 = str4.count();
    int len2 = str4.size();
    int len3 = str4.length();
    //长度为5
    qDebug() << len1;
    qDebug() << len2;
    qDebug() << len3;

空格整理

//去除首尾空格  trimmed
    QString str10 = "           OK                OK                OK            ";
    qDebug() << str10;
    QString str11 = str10.trimmed();
    qDebug() << str11;

    //统一空格格式
    QString str12 = "           OK                OK                OK            ";
    QString str13 = str12.simplified();
    qDebug() << str13;

查找字符串元素

//获取文件名
    QString str14 = "C:\\software\\IDA_Pro_v8.3_Portable\\ida64.exe";
    int last = str14.lastIndexOf("\\");     //截取最后一个'\'之后的字符元素下标，由于'\'是转义字符，所以此处打两个
    int exe = str14.indexOf(".exe");        //截取.exe之前的字符元素下标，这样就能获取文件名了
    qDebug() << last << "  " << exe;        //打印文件下标，分别是[33]和[39]

判断字符串是否为空

//判断字符串是否为空： isNull,isEmpty
    QString str15;
    QString str16 = "";

    qDebug() << str15.isNull() << "  " << str15.isEmpty();  //结果都返回true
    qDebug() << str16.isNull() << "  " << str16.isEmpty();  //前者返回false，即包含'\0'

判断是否包含某字符串

//判断是否包含某个字符串
    QString str17 = "Fuck you";
    //是否包含Fuck
    int index = str17.contains("fuck",Qt::CaseInsensitive);   //包含则返回1，否则返回0
    //CaseSensitive区分大小写，CaseInsensitive不区分大小写
    if(index){
        str17 = "F**k you";
    }
    qDebug() << str17;

判断字符串以某前缀开头/后缀结尾

//是否以特定后缀结尾 ".exe" and ".elf"
    QString pe = "test.exe";
    bool isexe = pe.endsWith(".exe",Qt::CaseSensitive);
    if(isexe)
        qDebug() << "It is a PE project.";
    else
        qDebug() << "It isn't a PE project.";

    //是否以特定字符串开头
    QString elf = "test.elf";
    bool istest = elf.startsWith("test",Qt::CaseInsensitive);
    if(istest)
        qDebug() << "O测试程序O";
    else
        qDebug() << "@非测试@";

完整代码

#include <QCoreApplication>
#include <QDebug>
#include <QString>

/*
QString 采用uniocde编码，每一个字符是一个16位的Qchar，即可兼容中文
*/

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QString str1 = "123";
    QString str2 = "456";

    // 数据转换 to int
    int a1 = str1.toInt();
    int a2 = str2.toInt();

    qDebug() << a1+a2;

    // 数字转QString
    int a3 = 520;                               // 208h
    QString str3 = QString::number(a3,16);      // 转为16进制

    qDebug() << str3;

    // 字符串拼接
    QString str4 = "hello";
    QString str5 = "_";
    QString str6 = "world";

    qDebug() << str4 + str5 + str6;             // "+"被重载了

    //转换大小写
    QString str7 = "Qt";
    QString str8 = str7.toLower();
    qDebug() << str8;
    QString str9 = str4.toUpper();
    qDebug() << str9;

    //判断字符长度： count/size/length
    int len1 = str4.count();
    int len2 = str4.size();
    int len3 = str4.length();
    //长度为5
    qDebug() << len1;
    qDebug() << len2;
    qDebug() << len3;

    //去除首尾空格  trimmed
    QString str10 = "           OK                OK                OK            ";
    qDebug() << str10;
    QString str11 = str10.trimmed();
    qDebug() << str11;

    //统一空格格式
    QString str12 = "           OK                OK                OK            ";
    QString str13 = str12.simplified();
    qDebug() << str13;

    //获取文件名
    QString str14 = "C:\\software\\IDA_Pro_v8.3_Portable\\ida64.exe";
    int last = str14.lastIndexOf("\\");     //截取最后一个'\'之后的字符元素下标，由于'\'是转义字符，所以此处打两个
    int exe = str14.indexOf(".exe");        //截取.exe之前的字符元素下标，这样就能获取文件名了
    qDebug() << last << "  " << exe;        //打印文件下标，分别是[33]和[39]

    //判断字符串是否为空： isNull,isEmpty
    QString str15;
    QString str16 = "";

    qDebug() << str15.isNull() << "  " << str15.isEmpty();  //结果都返回true
    qDebug() << str16.isNull() << "  " << str16.isEmpty();  //前者返回false，即包含'\0'

    //判断是否包含某个字符串
    QString str17 = "Fuck you";
    //是否包含Fuck
    int index = str17.contains("fuck",Qt::CaseInsensitive);   //包含则返回1，否则返回0
    //CaseSensitive区分大小写，CaseInsensitive不区分大小写
    if(index){
        str17 = "F**k you";
    }
    qDebug() << str17;

    //是否以特定后缀结尾 ".exe" and ".elf"
    QString pe = "test.exe";
    bool isexe = pe.endsWith(".exe",Qt::CaseSensitive);
    if(isexe)
        qDebug() << "It is a PE project.";
    else
        qDebug() << "It isn't a PE project.";

    //是否以特定字符串开头
    QString elf = "test.elf";
    bool istest = elf.startsWith("test",Qt::CaseInsensitive);
    if(istest)
        qDebug() << "O测试程序O";
    else
        qDebug() << "@非测试@";

    return a.exec();
}

运行效果