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ERR: Can't initialise DataFrame using empty Series and empty columns #34977

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@MarcoGorelli

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@MarcoGorelli
  • 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.


noticed while working on #30858

Note: Please read this guide detailing how to provide the necessary information for us to reproduce your bug.

Code Sample, a copy-pastable example

This returns an error:

>>> import pandas as pd
>>> pd.DataFrame(pd.Series([]), columns=[])
<stdin>:1: DeprecationWarning: The default dtype for empty Series will be 'object' instead of 'float64' in a future version. Specify a dtype explicitly to silence this warning.
Traceback (most recent call last):
  File "/home/marco/pandas-dev/pandas/core/internals/managers.py", line 1613, in create_block_manager_from_blocks
    make_block(values=blocks[0], placement=slice(0, len(axes[0])))
  File "/home/marco/pandas-dev/pandas/core/internals/blocks.py", line 2728, in make_block
    return klass(values, ndim=ndim, placement=placement)
  File "/home/marco/pandas-dev/pandas/core/internals/blocks.py", line 121, in __init__
    raise ValueError(
ValueError: Wrong number of items passed 1, placement implies 0

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/marco/pandas-dev/pandas/core/frame.py", line 488, in __init__
    mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
  File "/home/marco/pandas-dev/pandas/core/internals/construction.py", line 234, in init_ndarray
    return create_block_manager_from_blocks(block_values, [columns, index])
  File "/home/marco/pandas-dev/pandas/core/internals/managers.py", line 1623, in create_block_manager_from_blocks
    raise construction_error(tot_items, blocks[0].shape[1:], axes, e)
ValueError: Empty data passed with indices specified.

But this doesn't:

>>> pd.DataFrame([], columns=[])
Empty DataFrame
Columns: []
Index: []

#### Problem description

[this should explain **why** the current behaviour is a problem and why the expected output is a better solution]

#### Expected Output

Empty DataFrame
Columns: []
Index: []


#### Output of ``pd.show_versions()``

<details>
INSTALLED VERSIONS
------------------
commit           : 6a6faf596bc1e3bf4078d4837f654d0f2f754820
python           : 3.8.3.final.0
python-bits      : 64
OS               : Linux
OS-release       : 5.4.0-37-generic
Version          : #41-Ubuntu SMP Wed Jun 3 18:57:02 UTC 2020
machine          : x86_64
processor        : x86_64
byteorder        : little
LC_ALL           : None
LANG             : en_GB.UTF-8
LOCALE           : en_GB.UTF-8

pandas           : 1.1.0.dev0+1944.g6a6faf596
numpy            : 1.18.5
pytz             : 2020.1
dateutil         : 2.8.1
pip              : 20.1.1
setuptools       : 47.3.1.post20200616
Cython           : 0.29.20
pytest           : 5.4.3
hypothesis       : 5.16.1
sphinx           : 3.1.1
blosc            : None
feather          : None
xlsxwriter       : 1.2.9
lxml.etree       : 4.5.1
html5lib         : 1.0.1
pymysql          : None
psycopg2         : None
jinja2           : 2.11.2
IPython          : 7.15.0
pandas_datareader: None
bs4              : 4.9.1
bottleneck       : 1.3.2
fsspec           : 0.7.4
fastparquet      : 0.4.0
gcsfs            : None
matplotlib       : 3.2.1
numexpr          : 2.7.1
odfpy            : None
openpyxl         : 3.0.3
pandas_gbq       : None
pyarrow          : 0.17.1
pytables         : None
pyxlsb           : None
s3fs             : 0.4.2
scipy            : 1.4.1
sqlalchemy       : 1.3.17
tables           : 3.6.1
tabulate         : 0.8.7
xarray           : 0.15.1
xlrd             : 1.2.0
xlwt             : 1.3.0
numba            : 0.48.0

</details>

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