正则表达式是个强大的东西

暂时先记录一个用法：

QString str = "Peak memory: KEY s";

QString data = "Peak memory: 24.1 s";

 

需要构建一个可以匹配 data 的正则表达式,模板为 str ，其中KEY代表需要提取的数据。

PS: 需要注意的是 生成表达式中各种空格时候 \\ 的用法，什么时候用一个，什么时候用2个或者4个，搞错了的话就不会进入if条件语句了。

#include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          using namespace std;void generateReg(const QString &data, const QString &str){	Q_ASSERT(str != NULL && "Wrong input");	QString dst = str.trimmed();		// generate reg expression	dst.replace(QRegExp("\\s+"), "(\?\:\\s+)");	dst.replace("KEY", "([1-9]+\\.{,1}[0-9]*)");	//dst = "Peak memory:(?:\\s+)([1-9]+\\.{,1}[0-9]*)(?:\\s+)s";	cout << "The reg pattern should be: " << "Peak memory:(?:\\s+)([1-9]+\\.{,1}[0-9]*)(?:\\s+)s" << endl;	cout << "The dst String:            " << dst.toStdString() << endl;	QRegExp rx(dst);	int pos = data.indexOf(rx);		if (pos > -1)	{		cout << endl << "RegExp worked:)" << endl;		QStringList capedStr = rx.capturedTexts();		qDebug() << capedStr;	}}int main(int argc, char *argv[]){	QApplication a(argc, argv);	QString str  = "Peak memory:   KEY s";	QString data = "Peak memory:   241 s";	generateReg(data, str);	return a.exec();}
         
        
       
      
     

　　结果如下：

 

[突然想起有的地方代码可能看不到，还是贴着文本格式备用]

// 突然想起有可能看不了图片

#include <QApplication>

#include <QtGui>

#include <QLabel>

#include <QString>

#include <iostream>

using namespace std;

void generateReg(const QString &data, const QString &str)

{

Q_ASSERT(str != NULL && "Wrong input");

QString dst = str.trimmed();

// generate reg expression

dst.replace(QRegExp("\\s+"), "(\?\:\\s+)");

dst.replace("KEY", "([1-9]+\\.{,1}[0-9]*)");

//dst = "Peak memory:(?:\\s+)([1-9]+\\.{,1}[0-9]*)(?:\\s+)s";

cout << "The reg pattern should be: " << "Peak memory:(?:\\s+)([1-9]+\\.{,1}[0-9]*)(?:\\s+)s" << endl;

cout << "The dst String: " << dst.toStdString() << endl;

QRegExp rx(dst);

int pos = data.indexOf(rx);

if (pos > -1)

{

cout << endl << "RegExp worked:)" << endl;

QStringList capedStr = rx.capturedTexts();

qDebug() << capedStr;

}

}

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

QString str = "Peak memory: KEY s";

QString data = "Peak memory: 241 s";

generateReg(data, str);

return a.exec();

}