Now note that the first regular expression has one capture group, whereas the second regular expres- sion has two capture groups. Thus, if the first regex matches, we have the index value in the first subgroup. If the second regex matches, we have the index value in the second submatch and the “see also” value in the third submatch. For this reason, we output the contents of the first plus the contents of the second submatch (one has a value and the other is empty) as value found: