Qt practical regular expressions

Regular expressions in Qt use QRegularExpression, you can use regular expressions to find strings, QString can use regular expressions QRegularExpression for string replacement, splitting, etc.

---

1. Find the URL in the string

#include <QDebug>
#include <QRegularExpression>

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

	// 简单的 URL 正则表达式
	QRegularExpression regExp("http://.+?\\.(com\\.cn|com)");
	
	//查找第一个 URL
	 QRegularExpressionMatch match1 = regExp.match("请把http://www.baidu.com和http://www.sina.com.cn打开");
	
	qDebug() << match1.captured(0);
	
	// 查找所有的 URL
	 QRegularExpressionMatchIterator iter = regExp.globalMatch("请把http://www.baidu.com和http://www.sina.com.cn打开");
	
	
	while (iter.hasNext()) 
	{
    
    
		QRegularExpressionMatch match2 = iter.next();
		qDebug() << match2.captured(0);
	}
	return 0;
} 

输出
“http://www.baidu.com”
“http://www.baidu.com”
“http://www.sina.com.cn”

---

Second, string replacement

#include <QDebug>
#include <QRegularExpression>

int main(int argc, char *argv[]) 
{
    
    
	//普通替换
	QString s = "Banana";
 	s.replace(QRegularExpression("a[mn]"), "ox");
 	qDebug() << s; // s == "Boxoxa"
 
	// 替换时使用正则捕捉到的第一组的内容, \\1 表示第一组
	QString t = "A <i>bon mot</i>.";
 	t.replace(QRegularExpression("<i>([^<]*)</i>"), "\\emph{\\1}");
	qDebug() << t; // t == "A \\emph{bon mot}."
	return 0;
}

---

Three, string split

#include <QDebug>
#include <QRegularExpression>

int main(int argc, char *argv[]) 
{
    
    
	QString str = "Some text\n\twith strange whitespace.";;
	QStringList list = str.split(QRegularExpression("\\s+")); // 用连续的多个空白字符进行字符串拆分，空格，回车等都是空白字符
	
	qDebug() << list; // list: [ "Some", "text", "with", "strange", "whitespace." ]
	return 0;
}