BUG: DataFrame([listlikes]) different shape if first listlike is Categorical · Issue #38845 · pandas-dev/pandas (original) (raw)

arrs =  [np.arange(0, 40, 10), np.arange(0, 40, 10), np.arange(0, 40, 10)]

arrs2 = arrs.copy()
arrs2[0] = pd.Categorical(arrs2[0])

df = pd.DataFrame(arrs)
df2 = pd.DataFrame(arrs2)
df3 = pd.DataFrame(arrs2[::-1])

>>> df.shape
(3, 4)
>>> df2.shape
(4, 3)
>>> df3.shape
(3, 4)

It's specific to Categorical, as we check isinstance(data[0], Categorical) in nested_data_to_arrays