qt开发杂记 - 爱码网

1.利用正则表达式拆分字符串

  QString str = "[ 1920 , 1080^22/33*55 ]";
  QStringList sl = str.mid( 1, str.size() - 2 ).split( QRegExp( "[,*/^]" ) );
  qDebug() << sl.first(); //第一个数字
  qDebug() << sl.last(); //第二个数字

2.toPointF()使用

#include <QVariant>
#include <QPointF>

  QPointF nn( 1.0, 2.0 );
  QVariant ss( nn );
  QPointF aa = ss.toPointF();
  double zx = aa.rx();
  double zz = aa.ry();

3.Qt写文件

#include <QCoreApplication>
#include<QFile>
#include <QDir>
#include <QTextStream>

int main( int argc, char* argv[] )
{
  QCoreApplication a( argc, argv );
  const QString& robotDir = QString( "C:/Users/zhangxiangbz/Desktop/untitled/" );
  QString m_infoFile = QString( "%1/station_list.ini" ).arg( robotDir );
  QDir roboDir( robotDir );
  if ( !roboDir.exists() )
  {
    roboDir.mkpath( robotDir );
  }
  else
  {
    int i = 1;
    QString b = QString( "%1" ).arg( i, 3, 10, QChar( \'0\' ) );//整形数据用0补全   001
    double L = 1.0;
    QString c = QString::number( L, \'f\', 2 );//位数控制
    double x = 3.1, y = 2.2, z = 3.14;
    int id = 2;
    QString str = QString( "id:%1 pose:[%2, %3, %4]" ).arg( id ).arg( c ).arg( y ).arg( z );
    QFile infoFile( m_infoFile );
    if ( infoFile.open( QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ) )//插入文件末尾
    {
      QTextStream out( &infoFile );
      out << str << "\n";//每次写入数据换行
    }
    infoFile.close();
  }
}