Sign in to follow this  
FGFS

nested for -- regex

Recommended Posts

Hi

Little confused. How to most simple output all matches. For ex.  .m_airport_map contains LSZA, LSZB, LSZH and many more. Now I want to

show by giving L as name all starting with L, giving LS all starting with LS etc.

Many thanks

 

          for (auto it = test.m_airport_map.begin(); it != test.m_airport_map.end(); it++)
          {

              auto mapEntry = (*it);
//              std::cout << mapEntry.first << std::endl;

            std::smatch m;
            std::regex e ("(name.c_str())(.*)");

            std::regex_match ( mapEntry.first, m, e );

            std::cout << "matches:" << std::endl;
            for (std::smatch::iterator it = m.begin(); it!=m.end(); ++it) {
              std::cout << *it << std::endl;
            }

}

Share this post


Link to post
Share on other sites

Cannot figure it out. Any help? Thanks

#include <string>
#include <iostream>

using namespace std;

int main() {
    string str = "world";
    string expr = "Hello, (str)! Expression: (4*2./20)";

    cout << str << endl;
    cout << expr << endl;
}
Outputs:
[tt]world
Hello, (str)! Expression: (4*2./20)[/tt]

And does not output:
[tt]world
Hello, world! Expression: 0.4[/tt]


On the other hand, the following code:
#include <iostream>
#include <sstream>
#include <string>

using namespace std;

int main() {
    string str = "world";
    ostringstream temp;
    temp << "Hello, " << str << "! Expression: " << (4*2./20);
    string expr = temp.str();

    cout << str << endl;
    cout << expr << endl;
}
... does output:
[tt]world
Hello, world! Expression: 0.4[/tt] Edited by fastcall22

Share this post


Link to post
Share on other sites
Here's a brief, complete program that uses regex to match output all names beginning with "LS" from a vector of candidate names.  Perhaps it will help.
 
#include <iostream>
#include <regex>
#include <string>
#include <vector>

std::vector<std::string> airport_map = {
  "LSZA", "LSZB", "LSZH", "LZBB", "OMFG"
};


int
main()
{
  std::regex re("^LS");
  for (auto const& name: airport_map)
  {
    if (std::regex_search(name, re))
    {
      std::cout << name << "\n";
    }
  }
}
Edited by Bregma

Share this post


Link to post
Share on other sites

Thanks Bregma but even debugging through I saw LS* airports for mapEntry.first in debugger which were not found.

 

vector<Flughafen*> loopAirportpush(const string &name)
{

      std::regex re("^LS"); // I want to use name here
          for (auto it = test.m_airport_map.begin(); it != test.m_airport_map.end(); it++)
          {

              auto mapEntry = (*it);

              if (std::regex_search(mapEntry.first, re))
              {
                std::cout << mapEntry.first << "\n";
              }

Share this post


Link to post
Share on other sites

     std::regex e ("(0)(.*)");

 

the above seems to work if 0 is the first char. Now I need to integrate the string name. Well I have a look tomorrow if nobody is faster.

Share this post


Link to post
Share on other sites

Again, I want to list all beginning with the string "name".

Something alike:

    std::regex e ("^"name);

 

is wrong. Moderators, if it's that easy, why don't you give the correct code and not some unusable handicrafts?

Share this post


Link to post
Share on other sites

But you have been given the correct solution already; see fastcall22's post above. If you don't understand it, then ask for clarification and we may answer to help you learn why and how it works, but spoon feeding a solution is not helping anyone.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this