langchain_core.prompts.prompt.PromptTemplate¶
class langchain_core.prompts.prompt.PromptTemplate[source]¶
Bases: StringPromptTemplate
A prompt template for a language model.
A prompt template consists of a string template. It accepts a set of parameters
from the user that can be used to generate a prompt for a language model.
The template can be formatted using either f-strings (default) or jinja2 syntax.
Security warning: Prefer using template_format=”f-string” instead oftemplate_format=”jinja2”, or make sure to NEVER accept jinja2 templates
from untrusted sources as they may lead to arbitrary Python code execution.
As of LangChain 0.0.329, Jinja2 templates will be rendered using
Jinja2’s SandboxedEnvironment by default. This sand-boxing should
be treated as a best-effort approach rather than a guarantee of security,
as it is an opt-out rather than opt-in approach.
Despite the sand-boxing, we recommend to never use jinja2 templates
from untrusted sources.
Example
from langchain_core.prompts import PromptTemplate
# Instantiation using from_template (recommended)
prompt = PromptTemplate.from_template("Say {foo}")
prompt.format(foo="bar")
# Instantiation using initializer
prompt = PromptTemplate(input_variables=["foo"], template="Say {foo}")
Create a new model by parsing and validating input data from keyword arguments.
Raises ValidationError if the input data cannot be parsed to form a valid model.
param input_types: Dict[str, Any] [Optional]¶
A dictionary of the types of the variables the prompt template expects.
If not provided, all variables are assumed to be strings.
param input_variables: List[str] [Required]¶
A list of the names of the variables the prompt template expects.