py_csv_reader.py 文件源码

def _open_file(self):
        # only apply _skip property at the beginning of the trajectory
        skip = self._data_source._skip[self._itraj] + self.skip if self._t == 0 else 0
        nt = self._data_source._skip[self._itraj] + self._data_source._lengths[self._itraj]

        # calculate an index set, which rows to skip (includes stride)
        skip_rows = np.empty(0)

        if skip > 0:
            skip_rows = np.zeros(nt)
            skip_rows[:skip] = np.arange(skip)

        if not self.uniform_stride:
            all_frames = np.arange(nt)
            skip_rows = np.setdiff1d(all_frames, self.ra_indices_for_traj(self._itraj), assume_unique=True)
        elif self.stride > 1:
            all_frames = np.arange(nt)
            if skip_rows is not None:
                wanted_frames = np.arange(skip, nt, self.stride)
            else:
                wanted_frames = np.arange(0, nt, self.stride)
            skip_rows = np.setdiff1d(
                all_frames, wanted_frames, assume_unique=True)

        self._skip_rows = skip_rows
        try:
            fh = open(self._data_source.filenames[self._itraj],
                      mode=self._data_source.DEFAULT_OPEN_MODE)
            self._file_handle = fh
        except EnvironmentError:
            self._logger.exception()
            raise