BUG: yaml.dump throws AttributeError on dataframe – problem with reduce?

[allefeld]

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of pandas.
• (optional) I have confirmed this bug exists on the master branch of pandas.

Please note

I have reported this problem for PyYAML as yaml/pyyaml#541, but one of the maintainers says that this cannot be fixed on their side, but is caused by the way Pandas implements reduce.

Code Sample, a copy-pastable example

Code:

import pandas as pd
import numpy as np
import yaml

x = pd.DataFrame({
    'a': np.array([1.0, 2.0])
})

yaml.dump(x)

Result:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/__init__.py", line 290, in dump
    return dump_all([data], stream, Dumper=Dumper, **kwds)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/__init__.py", line 278, in dump_all
    dumper.represent(data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 27, in represent
    node = self.represent_data(data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 52, in represent_data
    node = self.yaml_multi_representers[data_type](self, data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 342, in represent_object
    return self.represent_mapping(
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 118, in represent_mapping
    node_value = self.represent_data(item_value)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 52, in represent_data
    node = self.yaml_multi_representers[data_type](self, data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 346, in represent_object
    return self.represent_sequence(tag+function_name, args)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 92, in represent_sequence
    node_item = self.represent_data(item)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 48, in represent_data
    node = self.yaml_representers[data_types[0]](self, data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 286, in represent_tuple
    return self.represent_sequence('tag:yaml.org,2002:python/tuple', data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 92, in represent_sequence
    node_item = self.represent_data(item)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 52, in represent_data
    node = self.yaml_multi_representers[data_type](self, data)
  File "/home/ca/.conda/envs/std/lib/python3.8/site-packages/yaml/representer.py", line 331, in represent_object
    if function.__name__ == '__newobj__':
AttributeError: 'functools.partial' object has no attribute '__name__'

Python 3.8.10 | packaged by conda-forge | (default, May 11 2021, 07:01:05)
PyYAML 5.4.1
Pandas 1.3.1
NumPy 1.21.1

Problem description

This prevents dataframes from being saved as YAML.

Output of pd.show_versions()

INSTALLED VERSIONS

commit : c7f7443
python : 3.8.10.final.0
python-bits : 64
OS : Linux
OS-release : 4.19.0-17-amd64
Version : #1 SMP Debian 4.19.194-3 (2021-07-18)
machine : x86_64
processor :
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8

pandas : 1.3.1
numpy : 1.21.1
pytz : 2021.1
dateutil : 2.8.2
pip : 21.2.1
setuptools : 49.6.0.post20210108
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.0.1
IPython : 7.25.0
pandas_datareader: None
bs4 : None
bottleneck : None
fsspec : 2021.07.0
fastparquet : None
gcsfs : None
matplotlib : None
numexpr : None
odfpy : None
openpyxl : 3.0.7
pandas_gbq : None
pyarrow : 5.0.0
pyxlsb : None
s3fs : None
scipy : 1.7.0
sqlalchemy : None
tables : None
tabulate : None
xarray : 0.19.0
xlrd : None
xlwt : None
numba : 0.53.1

[allefeld]

If this can't or won't be fixed, I'd be grateful for a tip reverting to which version of Pandas might be a workaround (last major changes to reduce).

Reverting to 1.2.5 is a workaround.

[jbrockmendel]

xref #42748

[phofl]

Closing as duplicate