我正在我的简单c++应用程序中使用pcre2(我正在使用vs2015)。
(我正在查看各种正则表达式库,并且总体感觉是pcre/pcre2是最灵活的)
首先,我从官方位置(http://sourceforge.net/projects/pcre/files/pcre2/10.20/)下载了pcre2,并创建了一个非常简单的示例。
#define PCRE2_CODE_UNIT_WIDTH 8
#include <pcre2.h>
...
PCRE2_SPTR subject = (PCRE2_SPTR)std::string("this is it").c_str();
PCRE2_SPTR pattern = (PCRE2_SPTR)std::string("([a-z]+)|\\s").c_str();
...
int errorcode;
PCRE2_SIZE erroroffset;
pcre2_code *re = pcre2_compile(pattern, PCRE2_ZERO_TERMINATED,
PCRE2_ANCHORED | PCRE2_UTF, &errorcode,
&erroroffset, NULL);
...
首先,文件“pcre2.h”不存在,因此我将pcre2.h.generic重命名为pcre2.h
但是然后我得到了 Unresolved external 链接器错误。
我猜我需要从源到项目包括一个或多个文件。
但是我不愿意只是随机添加文件而不知道它的全部作用。
有人可以给出一些简单的步骤来遵循以使用pcre2成功构建项目吗?
更新
这不是导入库问题,pcre2.h并不带有librar(我在其发布位置中看不到)。
最佳答案
如果您不介意使用包装器,请访问:JPCRE2
您需要根据将使用的字符串类(分别为char
,wchar_t
,char16_t
,char32_t
)选择基本字符类型(std::string
,std::wstring
,std::u16string
,std::u32string
):
typedef jpcre2::select<char> jp;
//Selecting char as the basic character type will require
//8 bit PCRE2 library where char is 8 bit,
//or 16 bit PCRE2 library where char is 16 bit,
//or 32 bit PCRE2 library where char is 32 bit.
//If char is not 8, 16 or 32 bit, it's a compile error.
匹配示例:
检查字符串是否与模式匹配:
if(jp::Regex("(\\d)|(\\w)").match("I am the subject"))
std::cout<<"\nmatched";
else
std::cout<<"\nno match";
全部匹配并获得匹配计数:
size_t count =
jp::Regex("(\\d)|(\\w)","mi").match("I am the subject", "g");
// 'm' modifier enables multi-line mode for the regex
// 'i' modifier makes the regex case insensitive
// 'g' modifier enables global matching
获取编号的子字符串/捕获的组:
jp::VecNum vec_num;
count =
jp::Regex("(\\w+)\\s*(\\d+)","im").initMatch()
.setSubject("I am 23, I am digits 10")
.setModifier("g")
.setNumberedSubstringVector(&vec_num)
.match();
std::cout<<"\nTotal match of first match: "<<vec_num[0][0];
std::cout<<"\nCaptrued group 1 of first match: "<<vec_num[0][1];
std::cout<<"\nCaptrued group 2 of first match: "<<vec_num[0][2];
std::cout<<"\nTotal match of second match: "<<vec_num[1][0];
std::cout<<"\nCaptrued group 1 of second match: "<<vec_num[1][1];
std::cout<<"\nCaptrued group 2 of second match: "<<vec_num[1][2];
获取命名的子字符串/捕获的组:
jp::VecNas vec_nas;
count =
jp::Regex("(?<word>\\w+)\\s*(?<digit>\\d+)","m")
.initMatch()
.setSubject("I am 23, I am digits 10")
.setModifier("g")
.setNamedSubstringVector(&vec_nas)
.match();
std::cout<<"\nCaptured group (word) of first match: "<<vec_nas[0]["word"];
std::cout<<"\nCaptured group (digit) of first match: "<<vec_nas[0]["digit"];
std::cout<<"\nCaptured group (word) of second match: "<<vec_nas[1]["word"];
std::cout<<"\nCaptured group (digit) of second match: "<<vec_nas[1]["digit"];
遍历所有匹配项和子字符串:
//Iterating through numbered substring
for(size_t i=0;i<vec_num.size();++i){
//i=0 is the first match found, i=1 is the second and so forth
for(size_t j=0;j<vec_num[i].size();++j){
//j=0 is the capture group 0 i.e the total match
//j=1 is the capture group 1 and so forth.
std::cout<<"\n\t("<<j<<"): "<<vec_num[i][j]<<"\n";
}
}
替换/替换示例:
std::cout<<"\n"<<
///replace all occurrences of a digit with @
jp::Regex("\\d").replace("I am the subject string 44", "@", "g");
///swap two parts of a string
std::cout<<"\n"<<
jp::Regex("^([^\t]+)\t([^\t]+)$")
.initReplace()
.setSubject("I am the subject\tTo be swapped according to tab")
.setReplaceWith("$2 $1")
.replace();
替换为匹配评估程序:
jp::String callback1(const jp::NumSub& m, void*, void*){
return "("+m[0]+")"; //m[0] is capture group 0, i.e total match (in each match)
}
int main(){
jp::Regex re("(?<total>\\w+)", "n");
jp::RegexReplace rr(&re);
String s3 = "I am ঋ আা a string 879879 fdsjkll ১ ২ ৩ ৪ অ আ ক খ গ ঘ আমার সোনার বাংলা";
rr.setSubject(s3)
.setPcre2Option(PCRE2_SUBSTITUTE_GLOBAL);
std::cout<<"\n\n### 1\n"<<
rr.nreplace(jp::MatchEvaluator(callback1));
//nreplace() treats the returned string from the callback as literal,
//while replace() will process the returned string
//with pcre2_substitute()
#if __cplusplus >= 201103L
//example with lambda
std::cout<<"\n\n### Lambda\n"<<
rr.nreplace(
jp::MatchEvaluator(
[](const jp::NumSub& m1, const jp::MapNas& m2, void*){
return "("+m1[0]+"/"+m2.at("total")+")";
}
));
#endif
return 0;
}
您可以阅读完整的文档here。
关于c++ - 在C++项目中使用pcre2,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/32580066/