Qt中的QString和QStringList常用方法

Posted 2021-07-20 smartvxworks

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,b=hello”

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0段, 保存到tmp
QString tmp = s.section(",", 0, 0);
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(即字符串为ASCII):
QByteArray tmp = ss.toLatin1();
char * buf3 = tmp.data();
//如果有中文(即字符串为unicode):
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/结束(startsWith/endsWith)
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
QStringList
//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”);