transform() — langchain Function Reference

Architecture documentation for the transform() function in passthrough.py from the langchain codebase.

Function python LangChainCore Runnables calls 1 called by 2

Entity Profile

LangChainCore→ Runnables→ transform() — langchain Function Reference

Dependency Diagram

graph TD
  8d2a37b9_a0ae_643b_9bbd_130393223126["transform()"]
  915f0e72_2130_6a8d_6929_3a7528446033["RunnablePassthrough"]
  8d2a37b9_a0ae_643b_9bbd_130393223126 -->|defined in| 915f0e72_2130_6a8d_6929_3a7528446033
  3e9c06ec_de75_0159_daf0_82c2499729cd["stream()"]
  3e9c06ec_de75_0159_daf0_82c2499729cd -->|calls| 8d2a37b9_a0ae_643b_9bbd_130393223126
  6b634a0f_8373_1838_7f85_ec4585108419["transform()"]
  6b634a0f_8373_1838_7f85_ec4585108419 -->|calls| 8d2a37b9_a0ae_643b_9bbd_130393223126
  6b634a0f_8373_1838_7f85_ec4585108419["transform()"]
  8d2a37b9_a0ae_643b_9bbd_130393223126 -->|calls| 6b634a0f_8373_1838_7f85_ec4585108419
  style 8d2a37b9_a0ae_643b_9bbd_130393223126 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/runnables/passthrough.py lines 253–281

    def transform(
        self,
        input: Iterator[Other],
        config: RunnableConfig | None = None,
        **kwargs: Any,
    ) -> Iterator[Other]:
        if self.func is None:
            for chunk in self._transform_stream_with_config(input, identity, config):
                yield chunk
        else:
            final: Other
            got_first_chunk = False

            for chunk in self._transform_stream_with_config(input, identity, config):
                yield chunk

                if not got_first_chunk:
                    final = chunk
                    got_first_chunk = True
                else:
                    try:
                        final = final + chunk  # type: ignore[operator]
                    except TypeError:
                        final = chunk

            if got_first_chunk:
                call_func_with_variable_args(
                    self.func, final, ensure_config(config), **kwargs
                )