前言:

ChatGPT如何计算token数？https://wtl4it.blog.csdn.net/article/details/135116493?spm=1001.2014.3001.5502https://wtl4it.blog.csdn.net/article/details/135116493?spm=1001.2014.3001.5502

GPT3.5\GPT4系列计算完整prompt token数的官方方法：

How to count tokens with tiktoken | OpenAI CookbookOpen-source examples and guides for building with the OpenAI API. Browse a collection of snippets, advanced techniques and walkthroughs. Share your own examples and guides.https://cookbook.openai.com/examples/how_to_count_tokens_with_tiktokenhttps://github.com/openai/openai-cookbook/blob/main/examples/How_to_count_tokens_with_tiktoken.ipynbhttps://github.com/openai/openai-cookbook/blob/main/examples/How_to_count_tokens_with_tiktoken.ipynb

计算的代码如下：

def num_tokens_from_messages(messages, model="gpt-3.5-turbo-0613"):"""Return the number of tokens used by a list of messages."""try:encoding = tiktoken.encoding_for_model(model)except KeyError:print("Warning: model not found. Using cl100k_base encoding.")encoding = tiktoken.get_encoding("cl100k_base")if model in {"gpt-3.5-turbo-0613","gpt-3.5-turbo-16k-0613","gpt-4-0314","gpt-4-32k-0314","gpt-4-0613","gpt-4-32k-0613",}:tokens_per_message = 3tokens_per_name = 1elif model == "gpt-3.5-turbo-0301":tokens_per_message = 4  # every message follows <|start|>{role/name}\n{content}<|end|>\ntokens_per_name = -1  # if there's a name, the role is omittedelif "gpt-3.5-turbo" in model:print("Warning: gpt-3.5-turbo may update over time. Returning num tokens assuming gpt-3.5-turbo-0613.")return num_tokens_from_messages(messages, model="gpt-3.5-turbo-0613")elif "gpt-4" in model:print("Warning: gpt-4 may update over time. Returning num tokens assuming gpt-4-0613.")return num_tokens_from_messages(messages, model="gpt-4-0613")else:raise NotImplementedError(f"""num_tokens_from_messages() is not implemented for model {model}. See https://github.com/openai/openai-python/blob/main/chatml.md for information on how messages are converted to tokens.""")num_tokens = 0for message in messages:num_tokens += tokens_per_messagefor key, value in message.items():num_tokens += len(encoding.encode(value))if key == "name":num_tokens += tokens_per_namenum_tokens += 3  # every reply is primed with <|start|>assistant<|message|>return num_tokens