rohitg00/ai-engineering-from-scratch · error · ValueError

bad slice: start={start} stop={stop}

Error message

bad slice: start={start} stop={stop}

What it means

Error "bad slice: start={start} stop={stop}" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/43-hdf5-tokenized-corpus/code/main.py:305

    def close(self) -> None:
        for file in self._files:
            try:
                file.close()
            except Exception:
                pass
        self._files = []
        self._datasets = []

    def __enter__(self) -> "MmapTokenStore":
        return self

    def __exit__(self, exc_type, exc, tb) -> None:
        self.close()

    def get_slice(self, start: int, stop: int) -> np.ndarray:
        if start < 0 or stop < 0 or stop < start:
            raise ValueError(f"bad slice: start={start} stop={stop}")
        if stop > self._total_tokens:
            raise ValueError(f"stop ({stop}) exceeds total tokens ({self._total_tokens})")
        if stop == start:
            return np.empty((0,), dtype=TOKEN_DTYPE)
        out = np.empty((stop - start,), dtype=TOKEN_DTYPE)
        cursor = 0
        for entry, dataset in zip(self._entries, self._datasets):
            shard_start = entry.global_start
            shard_stop = shard_start + entry.token_count
            if stop <= shard_start:
                break
            if start >= shard_stop:
                continue
            local_start = max(0, start - shard_start)
            local_stop = min(entry.token_count, stop - shard_start)
            length = local_stop - local_start
            if length <= 0:
                continue

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/43-hdf5-tokenized-corpus/code/main.py:305 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/a08d81e6094c20f6. Report an issue: GitHub.