# -> Tell me a funny joke about chickens.
Currently, PromptTemplate only supports jinja2 and f-string templating format. If there is any other templating format that you would like to use, feel free to open an issue in the Github page.
Validate template#
By default, PromptTemplate will validate the template string by checking whether the input_variables match the variables defined in template. You can disable this behavior by setting validate_template to False
template = "I am learning langchain because {reason}."
prompt_template = PromptTemplate(template=template, 
                                 input_variables=["reason", "foo"]) # ValueError due to extra variables
prompt_template = PromptTemplate(template=template, 
                                 input_variables=["reason", "foo"], 
                                 validate_template=False) # No error
Serialize prompt template#
You can save your PromptTemplate into a file in your local filesystem. langchain will automatically infer the file format through the file extension name. Currently, langchain supports saving template to YAML and JSON file.
prompt_template.save("awesome_prompt.json") # Save to JSON file
from langchain.prompts import load_prompt
loaded_prompt = load_prompt("awesome_prompt.json")
assert prompt_template == loaded_prompt
langchain also supports loading prompt template from LangChainHub, which contains a collection of useful prompts you can use in your project. You can read more about LangChainHub and the prompts available with it here.
from langchain.prompts import load_prompt
prompt = load_prompt("lc://prompts/conversation/prompt.json")
prompt.format(history="", input="What is 1 + 1?")
You can learn more about serializing prompt template in How to serialize prompts.
Pass few shot examples to a prompt template#
Few shot examples are a set of examples that can be used to help the language model generate a better response.
rtdocs_stable/api.python.langchain.com/en/stable/modules/prompts/prompt_templates/getting_started.html