BUG: Creating an empty dataframe

[simon-spier0]

An empty dataframe can't be created because this error is raised when I try it:
AttributeError: type object 'object' has no attribute 'dtype'

column_names = ["a", "b", "c"]
df = pd.DataFrame([], columns=column_names)

Based on this, it's caused by numpy version. If I install numpy 1.19.5, empty dataframe is created but if I install numpy 1.20.0 (or newer), the error above is raised.

Can this bug be fixed in pandas or in numpy?

Thank you.

[phofl]

This works for me on master with numpy 1.20

Please show your versions and traceback

INSTALLED VERSIONS ------------------ commit : b835ca2 python : 3.8.6.final.0 python-bits : 64 OS : Linux OS-release : 5.8.0-44-generic Version : #50~20.04.1-Ubuntu SMP Wed Feb 10 21:07:30 UTC 2021 machine : x86_64 processor : x86_64 byteorder : little LC_ALL : None LANG : en_US.UTF-8 LOCALE : en_US.UTF-8

pandas : 1.3.0.dev0+909.gb835ca2fc2
numpy : 1.20.0
pytz : 2020.5
dateutil : 2.8.1
pip : 20.3.3
setuptools : 49.6.0.post20210108
Cython : 0.29.21
pytest : 6.2.1
hypothesis : 6.0.2
sphinx : 3.4.3
blosc : None
feather : None
xlsxwriter : 1.3.7
lxml.etree : 4.6.2
html5lib : 1.1
pymysql : None
psycopg2 : None
jinja2 : 2.11.2
IPython : 7.19.0
pandas_datareader: None
bs4 : 4.9.3
bottleneck : 1.3.2
fsspec : 0.8.5
fastparquet : 0.5.0
gcsfs : 0.7.1
matplotlib : 3.3.3
numexpr : 2.7.2
odfpy : None
openpyxl : 3.0.6
pandas_gbq : None
pyarrow : 1.0.0
pyxlsb : None
s3fs : 0.4.2
scipy : 1.6.0
sqlalchemy : 1.3.22
tables : 3.6.1
tabulate : 0.8.7
xarray : 0.16.2
xlrd : 2.0.1
xlwt : 1.3.0
numba : 0.52.0

Process finished with exit code 0

[simon-spier0]

Traceback (most recent call last):

  File "C:\Program Files\JetBrains\PyCharm 2020.3.3\plugins\python\helpers\pydev\pydevd.py", line 1477, in _exec

    pydev_imports.execfile(file, globals, locals)  # execute the script

  File "C:\Program Files\JetBrains\PyCharm 2020.3.3\plugins\python\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile

    exec(compile(contents+"\n", file, 'exec'), glob, loc)

  File "C:/Users/x/Desktop/mtest1/execute.py", line 5, in <module>

    df = pd.DataFrame([], columns=column_names)

  File "C:\Users\x\.virtualenvs\mtest1-YxEr--ER\lib\site-packages\pandas\core\frame.py", line 490, in __init__

    mgr = init_dict({}, index, columns, dtype=dtype)

  File "C:\Users\x\.virtualenvs\mtest1-YxEr--ER\lib\site-packages\pandas\core\internals\construction.py", line 239, in init_dict

    val = construct_1d_arraylike_from_scalar(np.nan, len(index), nan_dtype)

  File "C:\Users\x\.virtualenvs\mtest1-YxEr--ER\lib\site-packages\pandas\core\dtypes\cast.py", line 1449, in construct_1d_arraylike_from_scalar

    dtype = dtype.dtype

AttributeError: type object 'object' has no attribute 'dtype'

python 3.8

numpy: 1.20.1
pandas: 1.0.1
python-dateutil: 2.8.1
pytz: 2021.1
six: 1.15.0

[phofl]

Please try on newer pandas, 1.2.3 came out yesterday

[simon-spier0]

Well, I see I have an older version of Pandas. It's ok now after update to the latest version. Sorry. :)