C++ regex_token_iterator Example


Example

A std::regex_token_iterator provides a tremendous tool for extracting elements of a Comma Separated Value file. Aside from the advantages of iteration, this iterator is also able to capture escaped commas where other methods struggle:

const auto input = "please split,this,csv, ,line,\\,\n"s;
const regex re{ "((?:[^\\\\,]|\\\\.)+)(?:,|$)" };
const vector<string> m_vecFields{ sregex_token_iterator(cbegin(input), cend(input), re, 1), sregex_token_iterator() };

cout << input << endl;

copy(cbegin(m_vecFields), cend(m_vecFields), ostream_iterator<string>(cout, "\n"));

Live Example

A notable gotcha with regex iterators is, that the regex argument must be an L-value. An R-value will not work.