Question

I have following code:

gchar **split = g_strsplit(str, "\n", 0);
gchar **pointer = NULL;
GRegex *line_regex = NULL;
GMatchInfo *info = NULL;
line_regex = g_regex_new("^.*:(\\d+):.*$", 0, 0, NULL);

gtk_list_store_clear(store);
gtk_list_store_clear(store);
for (pointer = split; *pointer; pointer++)
    if (strlen(*pointer)){
        gchar *word = "";
        if (line_regex && g_regex_match(line_regex, *pointer, 0, &info)){
            if (g_match_info_matches(info)){
                word = g_match_info_fetch(info, 0);
            }
        }
        gtk_list_store_insert_with_values(store, NULL, -1, 0, word, 1, *pointer, -1);
    }

I would like to get value inside the group, which means for following string:

some-test:56:some-other-text

I would like to get 56. I have no idea how gtk works, so I am a little blind here and I haven’t found anything in docs. In python I would use groups methods, so here I would need something similar. Could you advise me how to get it?

Answer 1

I found useful information at gnome.org’s g-match-info-fetch page which indicates that g_match_info_fetch(info, 0) returns the whole match, which for your ^ ... $ regex is the whole line. The code shown below (which is like your code, except I replaced gtk_list_store stuff with a printf) illustrates that g_match_info_fetch(info, 1) returns the field you want. The code displays the following 3 lines:

info 1 =   56,   info 0 = a-test:56:some-other-text
No match in b-test:283B:some-other-text
info 1 =  718,   info 0 = c-test:718:some-other-text

Here’s the code:

#include <string.h>
#include <gtk/gtk.h>
int main(void) {
  char *str = "a-test:56:some-other-text\nb-test:283B:some-other-text\nc-test:718:some-other-text\n";
  gchar **split = g_strsplit(str, "\n", 0);
  gchar **pointer = NULL;
  GRegex *line_regex = NULL;
  GMatchInfo *info = NULL;
  line_regex = g_regex_new("^.*:(\\d+):.*$", 0, 0, NULL);

  for (pointer = split; *pointer; pointer++)
    if (strlen(*pointer)) {
      if (line_regex && g_regex_match(line_regex, *pointer, 0, &info)) {
        if (g_match_info_matches(info)) {
          printf ("info 1 = %4s,   info 0 = %s\n",
              g_match_info_fetch(info, 1),
              g_match_info_fetch(info, 0));
        }
      } else
        printf ("No match in %s\n", *pointer);
    }
  return (0);
}