parameters: (self, diff_file, matching_string)
return_statement: return count
docstring: Returns the difference between the number of string occurences in
          the added lines and deleted lines (which one is subtracted from the
          other depends on _index_for_zero_value).
docstring_summary: Returns the difference between the number of string occurences in
          the added lines and deleted lines (which one is subtracted from the
          other depends on _index_for_zero_value).
docstring_tokens: Returns the difference between the number of string occurences in the added lines and deleted lines ( which one is subtracted from the other depends on _index_for_zero_value ) .
function: def _instance_difference(self, diff_file, matching_string):
          '''Returns the difference between the number of string occurences in
          the added lines and deleted lines (which one is subtracted from the
          other depends on _index_for_zero_value).'''
          count = 0
          for diff_line in diff_file:
              # If the line is unchanged, then don't examine it.
              if diff_line[self._index_for_zero_value] and diff_line[1 - self._index_for_zero_value]:
                  continue
              location_found = -len(matching_string)
              while True:
                  location_found = diff_line[2].find(matching_string, location_found + len(matching_string))
                  if location_found == -1:
                      break
                  if not diff_line[self._index_for_zero_value]:
                      count += 1
                  else:
                      count -= 1
          return count
function_tokens: def _instance_difference ( self , diff_file , matching_string ) : count = 0 for diff_line in diff_file : # If the line is unchanged, then don't examine it. if diff_line [ self . _index_for_zero_value ] and diff_line [ 1 - self . _index_for_zero_value ] : continue location_found = - len ( matching_string ) while True : location_found = diff_line [ 2 ] . find ( matching_string , location_found + len ( matching_string ) ) if location_found == - 1 : break if not diff_line [ self . _index_for_zero_value ] : count += 1 else : count -= 1 return count