使用正则表达式和C ++从字符串获取全名和值

Question

I have a project where I am reading data from a text file in c++ which contains a person's name and up to 4 numerical numbers like this. (each line has an entry)

Dave Light 89 71 91 89
Hua Tran Du 81 79 80 

I am wondering if regex would be an efficient way of splitting the name and numerical values or if I should find an alternative method.

I would also like to be able to pick up any errors in the text file when reading each entry such as a letter instead of a number as if an entry like this was found.

Andrew Van Den J 88 95 85

Answer 1

This non -regex solution:

std::string str = "Dave Light 89 71 91 89";
std::size_t firstDig = str.find_first_of("0123456789");
std::string str1 = str.substr (0,firstDig);
std::string str2 = str.substr (firstDig);

would give you the letter part in str1 and the number part in str2.

Check this code at ideone.com .

It sounds like it's something like this you want...(?) I'm not quite sure what kind of errors you mean to pick. As paxdiablo pointed out, a name could be quite complex, so getting the letter part probably would be the safest.

Answer 2

You should better use a separator instead of space. The separator could be : , | , ^ or anything that cannot be part of your data. With this approach, your data should be stored as:

Dave Light:89:71:91:89
Hua Tran Du:81:79:80 

And then you can use find , find_first_of , strchr or strstr or any other searching (and re-searching) to find relevant data.

Answer 3

Try this code.

#include <iostream>
#include <regex>
#include <string>
#include <vector>

int main(){
    std::vector<std::string> data {"Dave Light 89 71 91 ","Hua Tran Du 81 79 80","zyx 1 2 3 4","zyx 1 2"};
    std::regex pat {R"((^[A-Za-z\s]*)(\d+)\s*(\d+)\s*(\d+)(\s*)$)"};
    for(auto& line : data) {
        std::cout<<line<<std::endl;
        std::smatch matches; // matched strings go here
        if (regex_search(line, matches, pat)) {
            //std::cout<<"size:"<<matches.size()<<std::endl;
            if (matches.size()==6)
                std::cout<<"Name:"<<matches[1].str()<<"\t"<<"data1:"<<matches[2].str()<<"\tdata2:"<<matches[3].str()<<"\tdata3:"<<matches[4].str()<<std::endl;
        }
    }
}

With regex number of lines code reduced greatly. Main trick in regex is using right pattern.

Hope this will help you.