06. Date format output parser (DatetimeOutputParser)

DatetimeOutputParser

DatetimeOutputParser can be used to parse the output of LLM into datetime format.

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from dotenv import load_dotenv

load_dotenv()

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True

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# Set up LangSmith tracking. https://smith.langchain.com
# !pip install langchain-teddynote
from langchain_teddynote import logging

# Enter a project name.
logging.langsmith("CH03-OutputParser")

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Start tracking LangSmith.
[project name]
CH03-OutputParser

reference

Format codeExplainationExample

%Y

4 digit year

2024

%y

2 digit year

24

%m

2 digit month

07

%d

2 digit day

04

%H

24 hour clock

14

%I

12-hour clock

02

%p

AM or PM

PM

%M

2 digits

45

%S

2 digit seconds

08

%f

Microseconds (6 digits)

000123

%z

UTC offset

+0900

%Z

Time zone name

KST

%a

Day of the week abbreviation

Thu

%A

All days of the week

Thursday

%b

Month Abbreviation

Jul

%B

Whole month

July

%c

Full date and time

Thu Jul 4 14:45:08 2024

%x

Full date

07/04/24

%X

Total time

14:45:08

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from langchain.output_parsers import DatetimeOutputParser
from langchain.prompts import PromptTemplate
from langchain_openai import ChatOpenAI

# Date and time output parser
output_parser = DatetimeOutputParser()
output_parser.format = "%Y-%m-%d"

# Template for answering user questions
template = """Answer the users question:\n\n#Format Instructions: \n{format_instructions}\n\n#Question: \n{question}\n\n#Answer:"""

prompt = PromptTemplate.from_template(
    template,
    partial_variables={
        "format_instructions": output_parser.get_format_instructions()
    },  Apply the instructions to the template

)

# Print the prompt contents
prompt

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PromptTemplate(input_variables=['question'], partial_variables={'format_instructions': "Write a datetime string that matches the following pattern: '%Y-%m-%d'.\n\nExamples: 0751-08-07, 0937-04-06, 0298-07-15\n\nReturn ONLY this string, no other words!"}, template='Answer the users question:\n\n#Format Instructions: \n{format_instructions}\n\n#Question: \n{question}\n\n#Answer:')

Create a chain.

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# Chain creates.
chain = prompt | ChatOpenAI() | output_parser

# Call the chain to get answers to your questions.
output = chain.invoke({"question": "Google 이 창업한 연도는?"})

Prints the results.

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# Convert result to string
output.strftime("%Y-%m-%d")

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'1998-09-04'