BUG: na_values dict form not working on index column

[anna-intellegens]

BUG: na_values dict form not working on index column

[asishm]

replacing the None in names with anything else (string) works fine.

[monsterkaran]

import io
import pandas as pd

file_contents = """
,x,y
MA,1,2
NA,2,1
OA,,3
"""

default_nan_values = set(["NA", "squid"])
names = [None, "x", "y"]
nan_mapping = {name: default_nan_values for name in names}
dtype = {0: "object", "x": "float32", "y": "float32"}

try:
df = pd.read_csv(
io.StringIO(file_contents),
index_col=0,
header=0,
engine="c",
dtype=dtype,
names=names,
na_values=nan_mapping,
keep_default_na=True,
)
print(df)
except Exception as e:
print(f"Error occurred: {e}")

[rhshadrach]

Thanks for the report, confirmed on main. Further investigations and PRs to fix are welcome!

[tomhoq]

take

[tomhoq]

@thomas-intellegens Sorry to bother, but in the issue post you mention that

The dict form of na_values seems to be the only way implied in the documentation to allow having no na values on a specific column

In case you might remember, was the documentation this one?

Because otherwise, I cannot find, in the docs, where such property is mentioned.

Thank you

[anna-intellegens]

In case you might remember, was the documentation this one?

Yeah, this was the section I was reading. Many thanks for taking a look at this