BUG: NameError: name 'pa' is not defined despite pyarrow is installed

[emmansh]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd
import pyarrow as pa

data = {
    "foo": ["A", "B", "C"],
    "prop": [0.5, 0.8, 0.7]
}

df = pd.DataFrame(data)

df["prop"].astype('float64[pyarrow]')

Issue Description

Cannot change a column type to float64[pyarrow]. The error I get is:

NameError: name 'pa' is not defined

Expected Behavior

I'd expect to get the column converted properly

0    0.5
1    0.8
2    0.7
Name: prop, dtype: double[pyarrow]

Installed Versions

INSTALLED VERSIONS

commit : 0691c5c
python : 3.12.8
python-bits : 64
OS : Darwin
OS-release : 24.1.0
Version : Darwin Kernel Version 24.1.0: Thu Oct 10 21:02:45 PDT 2024; root:xnu-11215.41.3~2/RELEASE_ARM64_T8112
machine : arm64
processor : arm
byteorder : little
LC_ALL : None
LANG : None
LOCALE : None.UTF-8

pandas : 2.2.3
numpy : 1.26.4
pytz : 2024.1
dateutil : 2.9.0.post0
pip : 24.2
Cython : None
sphinx : None
IPython : 8.27.0
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : 4.12.3
blosc : None
bottleneck : 1.4.2
dataframe-api-compat : None
fastparquet : None
fsspec : None
html5lib : None
hypothesis : None
gcsfs : None
jinja2 : 3.1.4
lxml.etree : None
matplotlib : 3.9.2
numba : None
numexpr : 2.10.1
odfpy : None
openpyxl : None
pandas_gbq : None
psycopg2 : None
pymysql : None
pyarrow : 17.0.0
pyreadstat : None
pytest : None
python-calamine : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlsxwriter : None
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None

[emmansh]

Seems related to #57928.

[rhshadrach]

Thanks for the report, cannot reproduce on main nor 2.2.x. Just prior to the astype line, can you try running:

import sys
print([e for e in sys.modules if "pyarrow" in e])

what is the output that you get?

[emmansh]

@rhshadrach –

import sys
print([e for e in sys.modules if "pyarrow" in e])

## ['pandas.compat.pyarrow', 'pyarrow._generated_version', 'pyarrow.util', 'pyarrow.lib', 'pyarrow.ipc', 'pyarrow.types', 'pyarrow']

---

It's also worth noting that this issue is replicated on two different machines (locally as above; and AWS Sagemaker notebook).

More info
I set up my virtual env this way:

conda create -n "foo" python=3.12

source activate base
source activate foo

conda install jupyterlab pandas seaborn matplotlib pyarrow

👆🏻And working inside foo virtual env results with the issue reported in my original post.

However
if I set the virtual env in the following way, no issue and works as expected:

conda create -n "bar" python=3.12

source activate base
source activate bar

conda install jupyterlab pandas=2.2.2 seaborn matplotlib pyarrow=17.0.0