How can I combine outputs from multiple Langchain prompts using SequentialChain?

Below is one way to modify your chain so that you collect the outputs from all three chains and then combine them into your desired result. The key idea is to update the SequentialChain's output_variables to include all intermediate outputs (i.e., person, country, and dob) and then format the final result.

For example, you can modify your code as follows:

PYTHONCopied
import os
from constent import openai_key

from langchain_community.llms import OpenAI
import streamlit as st

from langchain import PromptTemplate
from langchain.chains import LLMChain, SequentialChain

os.environ["OPENAI_API_KEY"] = openai_key

st.title('Search about person')

input_text = st.text_input("Search about the person")

llm = OpenAI(temperature=1.0)

# Prompt for full name
prompt1 = PromptTemplate(
  input_variables=["name"],  # placeholder for storing the text
  template="Give the full name of {name}"
)
chain1 = LLMChain(llm=llm, prompt=prompt1, verbose=True, output_key='person')

# Prompt for country name
prompt2 = PromptTemplate(
  input_variables=["person"],  # placeholder for storing the text
  template="Give the name of the country that {person} belongs to?"
)
chain2 = LLMChain(llm=llm, prompt=prompt2, verbose=True, output_key='country')

# Prompt for date of birth
prompt3 = PromptTemplate(
  input_variables=["person"],
  template="What is the date of birth of {person}?"
)
chain3 = LLMChain(llm=llm, prompt=prompt3, verbose=True, output_key='dob')

# Modify the SequentialChain to output all results
combined_chain = SequentialChain(
  chains=[chain1, chain2, chain3],
  input_variables=["name"],
  output_variables=["person", "country", "dob"],
  verbose=True
)

if input_text:
    results = combined_chain.run({"name": input_text})
    # Format the final output as desired
    full_output = f"{results['person']} and the date of birth is {results['dob']}. He is from {results['country']}"
    st.write(full_output)

Explanation

• Step 1: We defined three separate prompts and their corresponding chains:
  • chain1 extracts the full name.
  • chain2 determines the country for that person.
  • chain3 retrieves the date of birth.
• Step 2: We set up the SequentialChain to return three output variables: "person", "country", and "dob".
• Step 3: After running the chain, we manually format the results to combine all outputs into your final desired string.

With these modifications, if you pass "Dhoni" as input, the final result should closely match your expected output.