将 2D 列表分配给 2 个数据框列 Pandas

Question

我尝试了以下操作并出现错误：>>> import pandas as pd>>> df = pd.DataFrame([[0,0],[2,2]])>>> df   0  10  0  01  2  2>>> y = [[0,0],[2,2],[3,3]]>>> df["s","d"] = yTraceback (most recent call last):  File "<stdin>", line 1, in <module>  File "C:\Python35\lib\site-packages\pandas\core\frame.py", line 3119, in __setitem__    self._set_item(key, value)  File "C:\Python35\lib\site-packages\pandas\core\frame.py", line 3194, in _set_item    value = self._sanitize_column(key, value)  File "C:\Python35\lib\site-packages\pandas\core\frame.py", line 3391, in _sanitize_column    value = _sanitize_index(value, self.index, copy=False)  File "C:\Python35\lib\site-packages\pandas\core\series.py", line 4001, in _sanitize_index    raise ValueError('Length of values does not match length of ' 'index')ValueError: Length of values does not match length of index>>> df[["s","d"]] = yTraceback (most recent call last):  File "<stdin>", line 1, in <module>  File "C:\Python35\lib\site-packages\pandas\core\frame.py", line 3116, in __setitem__    self._setitem_array(key, value)  File "C:\Python35\lib\site-packages\pandas\core\frame.py", line 3142, in _setitem_array    indexer = self.loc._convert_to_indexer(key, axis=1)  File "C:\Python35\lib\site-packages\pandas\core\indexing.py", line 1327, in _convert_to_indexer    .format(mask=objarr[mask]))KeyError: "['s' 'd'] not in index"让我知道如何同时使用二维数组创建 2 列。

Answer 1

您无法在尝试时直接执行此操作，但这是一种解决方法：

import pandas as pd

df = pd.DataFrame([[0,0],[2,2]])

y = [[0,0],[2,2]]

df["s"], df["d"] = [i[0] for i in y], [i[1] for i in y]

你有一些问题，其中之一df['s', 'd']是不正确的索引，你需要df[['s', 'd']]- 但你也不能直接从列表分配给它。

你也不能分配比索引长的任何东西，所以你y = [[0,0],[2,2],[3,3]]太长了。