def findAllByRow(self, target):
        """ Returns an array of rows in the region (defined by the raster), each
        row containing all matches in that row for the target pattern. """
        row_matches = []
        for row_index in range(self._raster[0]):
            row = self.getRow(row_index)
            row_matches[row_index] = row.findAll(target)
        return row_matches