Re: very basic question: read lines from file, split each line on tab and put that into an array, store a specific element of array

Hi red floyd,

Thanks very much for the answer. I'm trying to implement it and having
a bit of trouble. (I'm completely new to C++.) Adding a "\t" delimiter
to the "getline" function gives me a continuous stream of tab-
delimited strings that are not organized according to line. I then
thought I'd use "getline" to get each line and store each line in a
variable called "line", and then within each successfully acquired
"line", I would use "getline" with a "\t" delimiter with the input
being "line", the variable I want to store each tab-delimited element
in being "element", and the delimiter, of course, being '\t'. That
didn't work:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using std::endl;
using std::string;
using std::cout;
using std::ifstream;
using std::vector;

int main () {
       string line;
       ifstream myfile ("/Users/efoss/sequencing/simple_base_count/
partial_accepted_hits_23350.sam");
       if (myfile.is_open()) {
               while (getline(myfile, line)) {
                       vector<string> elements;
                       string element;
                       while (getline(line&, element, '\t')) {
                               elements.push_back(element);
                       }
                       for (int i = 0; i != elements.size(), ++i) {
                               cout << i << "\t" << elements[i] << endl;
                       }
               }
               myfile.close();
       }

       else cout << "Unable to open file " << myfile << endl;
       cout << "done!" << endl;
   return 0;
}

____________________________

I then Googled around for information on istringstream and
istream_iterator. I came across a post of yours on another site:

http://bytes.com/topic/c/answers/167600-split-string

Based on this, I made this .h file (which I called
"split_on_tab_060411_1.h"):

#ifndef GUARD_split_on_tab_060411_1
#define GUARD_split_on_tab_060411_1

#include <string>
#include <vector>

std::vector<std::string> split(const std::string&);

#endif

__________________________

I made this .cpp file (which I called "split_on_tab_060411_1.cpp"):

#include "split_on_tab_060411_1.h"
#include <string>
#include <sstream>
#include <iterator>
#include <vector>

using std::vector;
using std::string;
using std::istream_iterator;
using std::istringstream;

vector<string> split(const string& s) {
       istringstream is(s);
       return vector<string>(istream_iterator<string>(is),
istream_iterator<string());
}

_______________________

and I made this main.cpp file (which I called
"reading_bases_060411_2.cpp"):

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using std::endl;
using std::string;
using std::cout;
using std::ifstream;
using std::vector;

int main () {
       string line;
       ifstream myfile ("/Users/efoss/sequencing/simple_base_count/
partial_accepted_hits_23350.sam");
       if (myfile.is_open()) {
               while (getline(myfile, line)) {
                       //at this point you have a string called "line"
                       //it gets successfully printed out if I uncomment the
following
line:
                       //cout << line << endl;
               }
               myfile.close();
       }

       else cout << "Unable to open file " << myfile << endl;
       cout << "done!" << endl;
   return 0;
}

______________________________

If I run just my main function without including the "split_on_tab"
files, everything is fine. I know that I'm reading in my lines fine,
since I can print them out. However, if I try to add in my
"split_on_tab" files and use the "split" function, then I can't get
anything to work. Do you see what I am doing wrong?

Thanks very much for the help.

Eric

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