Comments (2)
From the latest pyarrow documentation
newlines_in_values, optional (default False)
Whether newline characters are allowed in CSV values. Setting this to True reduces the performance of multi-threaded CSV reading.
Enabling it by default would probably be a mistake. The pyarrow engine (with its multi-threaded capabilities) is the preferred option for large CSV files, though, so it'd be a shame for it to fail in this scenario.
If the pyarrow engine is here to stay, I'd recommend exposing newlines_in_values
to the user.
from pandas.
To keep the pyarrow engine, you'll need to use the pyarrow library directly to handle CSV files that contain newline characters. This involves using the ParseOptions class from pyarrow.csv to set the newlines_in_values option to True.
Example
import pyarrow as pa
import pandas as pd
rows = []
for i in range(1_000_000):
rows.append({"text": "ab\ncd", "i": i})
df = pd.DataFrame(rows)
# Define parse options to allow newlines in values
parse_options = pv.ParseOptions(newlines_in_values=True)
# Read the CSV file using pyarrow
table = pv.read_csv("example.csv", parse_options=parse_options)
# Convert the Arrow Table to a Pandas DataFrame
df = table.to_pandas()
df
from pandas.
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from pandas.