QString与QStringList

原文链接https://blog.csdn.net/zhu522959034/article/details/80279873

QString

//QString定义
QString s1 = "abc";
QString s2("hello");
//字符串连接
QString s = s1 + s2;

//组包
s = QString("a = %1, b = %2, c = %3").arg(250).arg("hello").arg(22.22);
qDebug()<<s;
//输出结果:a = 250, b = hello, c = 22.22

s = "a=250,b=hello,c=22.22";
//参数表示按逗号分隔, 拆分出第0段到第1段, 保存到tmp
QString tmp = s.section(",", 0, 1);
qDebug()<<"tmp = "<<tmp;
//输出结果:tmp="a=250"

tmp = tmp.section("=", 1, 1);
qDebug()<<"tmp="<<tmp;
//输出结果:tmp="250";

//QString转int
int a = tmp.toInt();
qDebug()<<"a="<<a;
//输出结果:a=250;

//int转QString组包方式转
tmp = QString("%1").arg(123);
qDebug()<<"tmp="<<tmp;
//输出结果:tmp="123"

//int转QString函数方式转
tmp = QString::number(234);

//char *转QString
const char * buf = "hello, world";
QString ss = buf;
qDebug()<<"ss = "<< ss;

//std::string转QString
string s = "hello, world"
QString ss = QString::fromStdString(s);
qDebug()<<"ss = "<< ss;

//std::wstring转QString
std::wstring wstr(L"你好, 世界");
QString ss = QString::fromStdWString(wstr);
qDebug()<<"ss = "<< ss;

//字符数组转QString
char buf2[100] = "hello world";
ss = buf2;
qDebug()<<"ss = "<<ss;

//QString转char *
ss = "hello abc";
//如果没有中文:
QByteArray tmp = ss.toLatin1();
char * buf3 = tmp.data();
//如果有中文:
QByteArray tmp = ss.toLocal8Bit();
char * buf4 = tmp.data();

//替换QString中字符串
QString text("text-decoration: none");
text.replace("none", "underline");

//去除QString首尾的空格(包括'\t', '\n', '\v', '\f', '\r')
QString text("   text-decoration: none   ");
text = text.trimmed();

//字符移除操作
QString test = "hello,china";
QString tmp = test.remove(2, 4);    //从下标2的字符开始, 移除4个字符
qDebug() << "test = " << test;    //输出hechina
qDebug() << "tmp = " << tmp;    //输出hechina

//判断字符是否以某字符或字符串开始
QString test= "@192.168.0.1";
if(true == test.startsWith("@"))
{
     //do something
}

//判断QString是否空
QString().isEmpty();             // return true
QString("").isEmpty();          // return true
QString(" ").isEmpty();         // return false
QString("abc").isEmpty();    // return false

QString().isNull();              // return true
QString("").isNull();           // return false
QString(" ").isNull();          // return false
QString("abc").isNull();     // return false

//获取子串
  QString str;
  QString csv = "forename,middlename,surname,phone";
  QString path = "/usr/local/bin/myapp"; // First field is empty
  QString::SectionFlag flag = QString::SectionSkipEmpty;

  str = csv.section(',', 2, 2);   // str == "surname"
  str = path.section('/', 3, 4);  // str == "bin/myapp"
  str = path.section('/', 3, 3, flag); // str == "myapp"

QString QString::mid(int position, int n = -1) const
  QString x = "Nine pineapples";
  QString y = x.mid(5, 4);            // y == "pine"
  QString z = x.mid(5);               // z == "pineapples"


//子串位置
  QString x = "sticky question";
  QString y = "sti";
  x.indexOf(y);               // returns 0
  x.indexOf(y, 1);            // returns 10
  x.indexOf(y, 10);           // returns 10
  x.indexOf(y, 11);           // returns -1

QStringList

类似字符串数组

//定义
QStringList list;
//添加字符串
list << "hello";
list << "world";
list.append("abc");
//例子2
QStringList chinaMonth;
        chinaMonth
            << QStringLiteral("正月")
            << QStringLiteral("二月")
            << QStringLiteral("三月")
            << QStringLiteral("四月")
            << QStringLiteral("五月")
            << QStringLiteral("六月")
            << QStringLiteral("七月")
            << QStringLiteral("八月")
            << QStringLiteral("九月")
            << QStringLiteral("十月")
            << QStringLiteral("冬月")
            << QStringLiteral("腊月")
            ;
//打印
qDebug()<< "list ="<< list;
//遍历
for(int i = 0; i< list.size();++i)
{
    QString tmp = list.at(i);
    qDebug()<<"tmp ="<< tmp; 
}

//使用QStringList拆分QString
QString str = "hello,world,abc,qt";
QStringList list2 = str.split(",");
qDebug()<<"list2="<<list2;
//输出:list2=("hello","world","abc","qt");

//判断QStringList中是否包含某个成员
bool b = list2.contains("123");

//移除QStringList中的成员
list2.removeOne("abc");

//迭代器
  QStringList qstrList;
  qstrList<<"Android" << "Qt Creator" << "Java" << "C++";
  QStringListIterator strIterator(qstrList);
  while (strIterator.hasNext())
        qDebug() << strIterator.next() << endl;


qstrList.insert(0,"C#");

qstrList.replace(0,"Web");

QString str = fonts.join(",");
// str == "Android,Qt Creator,Java,C++"

QString str = "Android,Qt Creator, ,Java,C++";
QStringList list1 = str.split(",");
// list1: [ "Android", "Qt Creator"," ", "Java", "C++" ]
QStringList list2 = str.split(",", QString::SkipEmptyParts);
// list2:[ "Android", "Qt Creator", "Java", "C++" ]