使用Vaex读取拼花地板文件

Question

我正在尝试使用Vaex将一些数据从拼花地板文件读入python

这是我使用vaex.open函数得到的输出

>>> import vaex
>>> trade = vaex.open('trade.parquet')
>>> trade
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 3703, in __repr__
    return self._head_and_tail_table(format='plain')
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 3464, in _head_and_tail_table
    return self._as_table(0, n, N - n, N, format=format)
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 3599, in _as_table
    parts = table_part(i1, i2, parts)
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 3573, in table_part
    df = self[k1:k2]
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 4626, in __getitem__
    df = self.trim()
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 3859, in trim
    df = self if inplace else self.copy()
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 5036, in copy
    df.add_column(name, column, dtype=self._dtypes_override.get(name))
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 6053, in add_column
    super(DataFrameArrays, self).add_column(name, data, dtype=dtype)
  File "/home/userman/.local/lib/python3.6/site-packages/vaex/dataframe.py", line 2942, in add_column
    raise ValueError("array is of length %s, while the length of the DataFrame is %s" % (len(ar), self.length_original()))
ValueError: array is of length 1048576, while the length of the DataFrame is 34421587

数据帧的长度是正确的，但我不明白1048576与什么有关。我发现了一个关于读取hdf5文件的previous answer，但它似乎与我的问题无关。数据最初从csv文件读取，然后使用pyarrow导出到拼花地板

有人能详细说明这个问题是什么以及如何解决它吗

Answer 1

我也有同样的问题，因此，我假设您使用的是vaex 3.x，请尝试最新的alpha 4.0.0a13，最好是在全新的虚拟环境中

pip install vaex==4.0.0a13

更新

截至3月9日，2021vaex 4已退出，并在pypi中标记为默认版本，因此不再需要指定版本

pip install vaex