Source code for langchain.output_parsers.pandas_dataframe
import re
from typing import Any, Union
from langchain_core.exceptions import OutputParserException
from langchain_core.output_parsers.base import BaseOutputParser
from pydantic import field_validator
from langchain.output_parsers.format_instructions import (
PANDAS_DATAFRAME_FORMAT_INSTRUCTIONS,
)
[docs]
class PandasDataFrameOutputParser(BaseOutputParser[dict[str, Any]]):
"""Parse an output using Pandas DataFrame format."""
"""The Pandas DataFrame to parse."""
dataframe: Any
@field_validator("dataframe")
@classmethod
def validate_dataframe(cls, val: Any) -> Any:
import pandas as pd
if issubclass(type(val), pd.DataFrame):
return val
if pd.DataFrame(val).empty:
raise ValueError("DataFrame cannot be empty.")
raise TypeError(
"Wrong type for 'dataframe', must be a subclass \
of Pandas DataFrame (pd.DataFrame)"
)
[docs]
def parse_array(
self, array: str, original_request_params: str
) -> tuple[list[Union[int, str]], str]:
parsed_array: list[Union[int, str]] = []
# Check if the format is [1,3,5]
if re.match(r"\[\d+(,\s*\d+)*\]", array):
parsed_array = [int(i) for i in re.findall(r"\d+", array)]
# Check if the format is [1..5]
elif re.match(r"\[(\d+)\.\.(\d+)\]", array):
match = re.match(r"\[(\d+)\.\.(\d+)\]", array)
if match:
start, end = map(int, match.groups())
parsed_array = list(range(start, end + 1))
else:
raise OutputParserException(
f"Unable to parse the array provided in {array}. \
Please check the format instructions."
)
# Check if the format is ["column_name"]
elif re.match(r"\[[a-zA-Z0-9_]+(?:,[a-zA-Z0-9_]+)*\]", array):
match = re.match(r"\[[a-zA-Z0-9_]+(?:,[a-zA-Z0-9_]+)*\]", array)
if match:
parsed_array = list(map(str, match.group().strip("[]").split(",")))
else:
raise OutputParserException(
f"Unable to parse the array provided in {array}. \
Please check the format instructions."
)
# Validate the array
if not parsed_array:
raise OutputParserException(
f"Invalid array format in '{original_request_params}'. \
Please check the format instructions."
)
elif (
isinstance(parsed_array[0], int)
and parsed_array[-1] > self.dataframe.index.max()
):
raise OutputParserException(
f"The maximum index {parsed_array[-1]} exceeds the maximum index of \
the Pandas DataFrame {self.dataframe.index.max()}."
)
return parsed_array, original_request_params.split("[")[0]
[docs]
def parse(self, request: str) -> dict[str, Any]:
stripped_request_params = None
splitted_request = request.strip().split(":")
if len(splitted_request) != 2:
raise OutputParserException(
f"Request '{request}' is not correctly formatted. \
Please refer to the format instructions."
)
result = {}
try:
request_type, request_params = splitted_request
if request_type in {"Invalid column", "Invalid operation"}:
raise OutputParserException(
f"{request}. Please check the format instructions."
)
array_exists = re.search(r"(\[.*?\])", request_params)
if array_exists:
parsed_array, stripped_request_params = self.parse_array(
array_exists.group(1), request_params
)
if request_type == "column":
filtered_df = self.dataframe[
self.dataframe.index.isin(parsed_array)
]
if len(parsed_array) == 1:
result[stripped_request_params] = filtered_df[
stripped_request_params
].iloc[parsed_array[0]]
else:
result[stripped_request_params] = filtered_df[
stripped_request_params
]
elif request_type == "row":
filtered_df = self.dataframe[
self.dataframe.columns.intersection(parsed_array)
]
if len(parsed_array) == 1:
result[stripped_request_params] = filtered_df.iloc[
int(stripped_request_params)
][parsed_array[0]]
else:
result[stripped_request_params] = filtered_df.iloc[
int(stripped_request_params)
]
else:
filtered_df = self.dataframe[
self.dataframe.index.isin(parsed_array)
]
result[request_type] = getattr(
filtered_df[stripped_request_params], request_type
)()
else:
if request_type == "column":
result[request_params] = self.dataframe[request_params]
elif request_type == "row":
result[request_params] = self.dataframe.iloc[int(request_params)]
else:
result[request_type] = getattr(
self.dataframe[request_params], request_type
)()
except (AttributeError, IndexError, KeyError):
if request_type not in {"column", "row"}:
raise OutputParserException(
f"Unsupported request type '{request_type}'. \
Please check the format instructions."
)
raise OutputParserException(
f"""Requested index {
request_params
if stripped_request_params is None
else stripped_request_params
} is out of bounds."""
)
return result
