有人可以解释为什么以下直线：
nbrs['d_inv'] = nbrs['d'].pow(-1)
...
nbrs[k] = nbrs[c] * nbrs['d_inv']
（k和c是键）每个都引发一个SettingWithCopyWarning：
SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
当我尝试在iPython中复制此行为时：
import pandas as pd
import numpy.random as rand
t = pd.DataFrame()
t['d'] = rand.uniform(0,1,5)
t['d_inv'] = t.pow(-1)
t['sum'] = t['d'] + t['d_inv']
没有提出警告。这里发生了什么？
[编辑1]我没有尝试做链式索引。我只是想填充一个空列。
[编辑2]
nbrs = pd.DataFrame（row_generator（））其中每一行都是Series：
===== ===== ===== =====
name = None
--------------------------
lat lon head d
===== ===== ===== =====
float float float float
===== ===== ===== =====
[edit 3] NOT A DUPLICATE
waring消息变得更不具体
使用nbrs.loc[:,'d_inv'] = nbrs['d'].pow(-1)加注
SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
self.obj[item_labels[indexer[info_axis]]] = value