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Description
Code Sample, a copy-pastable example if possible
df=DataFrame([1,2,3,4],[4,5,6,7], columns= [list('abcd'), list('cdef')])Problem description
when creating DataFrame by list of list with multiIndex, raise ValueError. I'm new to pandas, I don't know why, but it seems like a bug...
d=DataFrame([[1,2,3,4],[4,5,6,7]], columns= [list('abcd'), list('cdef')])
Traceback (most recent call `last):
File "<ipython-input-70-b1022cf50f33>", line 1, in <module>
d=DataFrame([[1,2,3,4],[4,5,6,7]], columns= [list('abcd'), list('cdef')])
File "D:\Users\tangliu\AppData\Local\Continuum\anaconda3\lib\site-packages\pandas\core\frame.py", line 450, in __init__
arrays, columns = to_arrays(data, columns, dtype=dtype)
File "D:\Users\tangliu\AppData\Local\Continuum\anaconda3\lib\site-packages\pandas\core\internals\construction.py", line 464, in to_arrays
return _list_to_arrays(data, columns, coerce_float=coerce_float, dtype=dtype)
File "D:\Users\tangliu\AppData\Local\Continuum\anaconda3\lib\site-packages\pandas\core\internals\construction.py", line 504, in _list_to_arrays
raise ValueError(e) from e
ValueError: 2 columns passed, passed data had 4 columns`
It's ok using numpy ndarray or something else
d=DataFrame([[1,2,3,4],[4,5,6,7]])
d
Out[72]:
0 1 2 3
0 1 2 3 4
1 4 5 6 7
d.columns=[list('abcd'),list('cdef')]
d
Out[74]:
a b c d
c d e f
0 1 2 3 4
1 4 5 6 7
it's ok when using numpy's ndarray
d=DataFrame(np.random.randn(6,4), columns=[list('abcd'), list('cdef')])
d
Out[81]:
a b c d
c d e f
0 -0.066216 -1.264157 -1.199212 -0.184394
1 0.413666 -0.310750 1.138304 -0.271516
2 0.263854 0.827858 0.652344 -0.024369
3 0.041060 -2.235779 0.707691 0.319255
4 -0.118407 -1.278394 0.398972 0.597036
5 0.048947 0.697497 2.168712 0.650022