mirror of
https://github.com/hwchase17/langchain
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87e502c6bc
Co-authored-by: jacoblee93 <jacoblee93@gmail.com> Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
94 lines
2.2 KiB
Plaintext
94 lines
2.2 KiB
Plaintext
```python
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from langchain.output_parsers import StructuredOutputParser, ResponseSchema
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from langchain.prompts import PromptTemplate, ChatPromptTemplate, HumanMessagePromptTemplate
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from langchain.llms import OpenAI
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from langchain.chat_models import ChatOpenAI
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```
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Here we define the response schema we want to receive.
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```python
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response_schemas = [
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ResponseSchema(name="answer", description="answer to the user's question"),
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ResponseSchema(name="source", description="source used to answer the user's question, should be a website.")
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]
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output_parser = StructuredOutputParser.from_response_schemas(response_schemas)
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```
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We now get a string that contains instructions for how the response should be formatted, and we then insert that into our prompt.
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```python
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format_instructions = output_parser.get_format_instructions()
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prompt = PromptTemplate(
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template="answer the users question as best as possible.\n{format_instructions}\n{question}",
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input_variables=["question"],
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partial_variables={"format_instructions": format_instructions}
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)
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```
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We can now use this to format a prompt to send to the language model, and then parse the returned result.
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```python
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model = OpenAI(temperature=0)
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```
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```python
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_input = prompt.format_prompt(question="what's the capital of france?")
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output = model(_input.to_string())
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```
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```python
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output_parser.parse(output)
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```
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<CodeOutputBlock lang="python">
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```
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{'answer': 'Paris',
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'source': 'https://www.worldatlas.com/articles/what-is-the-capital-of-france.html'}
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```
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</CodeOutputBlock>
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And here's an example of using this in a chat model
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```python
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chat_model = ChatOpenAI(temperature=0)
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```
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```python
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prompt = ChatPromptTemplate(
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messages=[
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HumanMessagePromptTemplate.from_template("answer the users question as best as possible.\n{format_instructions}\n{question}")
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],
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input_variables=["question"],
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partial_variables={"format_instructions": format_instructions}
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)
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```
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```python
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_input = prompt.format_prompt(question="what's the capital of france?")
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output = chat_model(_input.to_messages())
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```
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```python
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output_parser.parse(output.content)
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```
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<CodeOutputBlock lang="python">
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```
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{'answer': 'Paris', 'source': 'https://en.wikipedia.org/wiki/Paris'}
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```
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</CodeOutputBlock>
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