Question

I am having a regex replace issue that i can’t seem to figure out for replacing some configured parameter for a file path.

Here is what I have so far:

The regex for a filepath may not be perfect but it seems to work ok.

regex: ^(?<path>[^\\/*?<>|]+)\\\\(?<filename>.+)\\.(?<ext>.mp4$)

file name match results name: $2

So what this is doing is searching a listing of files where the extension is mp4 and using the configured match result, it will return that as a “file name”.

Target string examples,

\\\\folder\music\hello.mp4

result filename = “hello”

What I would like to do is be able to take either the results from a regex match and be able to replace the name of the file/extension/path by a configured setting.

So If someone wanted for all the matched results to replace the file name with “goodbye”, how would i accomplish this. This is what i have now.

std::string sz_regex_pattern("^(?<path>[^\/*?<>|]+)\\(?<filename>.+)\.(?<ext>.mp4$)");
boost::cmatch rm;
boost::regex pattern(sz_regex_pattern, regex::icase|regex_constants::perl);
std::string complete_file_name_path = "\\folder\music\hello.mp4";
bool result = boost::regex_match(complete_file_name_path , rm, pattern);
std::string old_filename= rm.format("$2"); // returns the name of the file only

What appears to work but limits it to a filename where the folder is not the same name so,
\\folder\music\hello\hello.mp4 would have issues with the regex_replace below.

std::string new_filename = "goodbye";

std::string sz_new_file_name_path = boost::regex_replace(complete_file_name_path, old_filename, new_filename);

so i can later,

boost::filesystem::rename(complete_file_name_path, sz_new_file_name_path);

Any help would be appreciated.

Answer 1

Find and replace is completely unnecessary because you already have all of the components you need to build the new path.

REPLACE

std::string sz_new_file_name_path = boost::regex_replace(complete_file_name_path, old_filename, new_filename);

WITH

// path + newFileName + ext
std::string sz_new_file_name_path = rm.format("$1") + "\\" + new_filename + "." + rm.format("$3")