C ++ regex_match不工作 [英] C++ regex_match not working
问题描述
这是我的代码的一部分
bool CSettings::bParseLine ( const char* input )
{
//_asm INT 3
std::string line ( input );
std::size_t position = std::string::npos, comment;
regex cvarPattern ( "\\.([a-zA-Z_]+)" );
regex parentPattern ( "^([a-zA-Z0-9_]+)\\." );
regex cvarValue ( "\\.[a-zA-Z0-9_]+[ ]*=[ ]*(\\d+\\.*\\d*)" );
std::cmatch matchedParent, matchedCvar;
if ( line.empty ( ) )
return false;
if ( !std::regex_match ( line.c_str ( ), matchedParent, parentPattern ) )
return false;
if ( !std::regex_match ( line.c_str ( ), matchedCvar, cvarPattern ) )
return false;
...
}
我尝试用它分隔行从文件读取 - 行如下:
I try to separate with it lines which I read from file - lines look like:
foo.bar = 15
baz.asd = 13
ddd.dgh = 66
,我想从中提取零件 - 例如对于第一行foo.bar = 15,我想结束如下:
and I want to extract parts from it - e.g. for 1st line foo.bar = 15, I want to end up with something like:
a = foo
b = bar
c = 15
但现在,regex总是返回false,在线regex检查,甚至在visual studio,它的工作很好,我需要一些不同的语法为C + + regex_match?我使用visual studio 2013社区
but now, regex is returning always false, I tested it on many online regex checkers, and even in visual studio, and it's working great, do I need some different syntax for C++ regex_match? I'm using visual studio 2013 community
推荐答案
问题是 std :: regex_match 必须匹配整个字符串,但您只尝试匹配它的一部分。
The problem is that std::regex_match must match the entire string but you are trying to match only part of it.
您需要使用 std :: regex_search 或更改您的正则表达式一次匹配所有三个部分:
You need to either use std::regex_search or alter your regular expression to match all three parts at once:
#include <regex>
#include <string>
#include <iostream>
const auto test =
{
"foo.bar = 15"
, "baz.asd = 13"
, "ddd.dgh = 66"
};
int main()
{
const std::regex r(R"~(([^.]+)\.([^\s]+)[^0-9]+(\d+))~");
// ( 1 ) ( 2 ) ( 3 ) <- capture groups
std::cmatch m;
for(const auto& line: test)
{
if(std::regex_match(line, m, r))
{
// m.str(0) is the entire matched string
// m.str(1) is the 1st capture group
// etc...
std::cout << "a = " << m.str(1) << '\n';
std::cout << "b = " << m.str(2) << '\n';
std::cout << "c = " << m.str(3) << '\n';
std::cout << '\n';
}
}
}
正则表达式: https://regex101.com/r/kB2cX3/2
输出:
a = foo
b = bar
c = 15
a = baz
b = asd
c = 13
a = ddd
b = dgh
c = 66
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