GPT-3.5 series is a series of models that was trained on a blend of text and code from before Q4 2021. The following models are in the GPT-3.5 series:

code-davinci-002 is a base model, so good for pure code-completion tasks

text-davinci-002 is an InstructGPT model based on code-davinci-002

text-davinci-003 is an improvement on text-davinci-002

gpt-3.5-turbo-0301 is an improvement on text-davinci-003, optimized for chat

最后一个其实就是ChatGPT