_pick() — langchain Function Reference

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

Function python LangChainCore Runnables calls 1 called by 3

Entity Profile

LangChainCore→ Runnables→ _pick() — langchain Function Reference

Dependency Diagram

graph TD
  3a36dbf6_6c2b_7362_1ddb_d7fe56086df3["_pick()"]
  8b44d2a6_6c89_4ea1_b8c7_64e60123bbbe["RunnablePick"]
  3a36dbf6_6c2b_7362_1ddb_d7fe56086df3 -->|defined in| 8b44d2a6_6c89_4ea1_b8c7_64e60123bbbe
  355d2fce_215e_3c1a_df77_1bc43c1f6aae["_ainvoke()"]
  355d2fce_215e_3c1a_df77_1bc43c1f6aae -->|calls| 3a36dbf6_6c2b_7362_1ddb_d7fe56086df3
  ce4d1e34_3bb5_37f8_6976_fc0c99c23892["_transform()"]
  ce4d1e34_3bb5_37f8_6976_fc0c99c23892 -->|calls| 3a36dbf6_6c2b_7362_1ddb_d7fe56086df3
  07dae0e0_e299_4a3b_4925_f46bdb69bdaf["_atransform()"]
  07dae0e0_e299_4a3b_4925_f46bdb69bdaf -->|calls| 3a36dbf6_6c2b_7362_1ddb_d7fe56086df3
  933ccc14_844d_c42a_d3ca_33f04cdfba48["assign()"]
  3a36dbf6_6c2b_7362_1ddb_d7fe56086df3 -->|calls| 933ccc14_844d_c42a_d3ca_33f04cdfba48
  style 3a36dbf6_6c2b_7362_1ddb_d7fe56086df3 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/runnables/passthrough.py lines 744–754

    def _pick(self, value: dict[str, Any]) -> Any:
        if not isinstance(value, dict):
            msg = "The input to RunnablePassthrough.assign() must be a dict."
            raise ValueError(msg)  # noqa: TRY004

        if isinstance(self.keys, str):
            return value.get(self.keys)
        picked = {k: value.get(k) for k in self.keys if k in value}
        if picked:
            return AddableDict(picked)
        return None