pandas 在train_test_split之后显示SettingWithCopyWarning [英] Pandas shows SettingWithCopyWarning after train_test_split

问题描述

我正在尝试处理从Sci-Kit Learn的 train_test_split 操作接收的数据帧.系统给我以下信息:

I'm trying to manipulate a dataframe that I received from Sci-Kit Learn's train_test_split operation. The system gives me the following:

/usr/local/lib/python3.6/site-packages/pandas/core/indexing.py:179: SettingWithCopyWarning:试图在一个副本上设置一个值 从DataFrame切片

/usr/local/lib/python3.6/site-packages/pandas/core/indexing.py:179: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame

以下内容在我的系统上发出警告:

The following raises the warning on my system:

import pandas as pd
from sklearn.model_selection import train_test_split
X=pd.DataFrame({'A':[2,5,7,8,9],'B':[2,5,3,51,5]})
(Xt,Xv)=train_test_split(X)
Xt.iloc[0,0]=6

我使用以下版本:

python:'3.6.1(默认，2017年6月26日，19:29:26)\ n [GCC 4.9.2]'

python: '3.6.1 (default, Jun 26 2017, 19:29:26) \n[GCC 4.9.2]'

熊猫:0.20.3

sklearn:0.18.2

sklearn: 0.18.2

推荐答案

您可以按照以下方法解决此问题:

You can workaround it as follows:

In [16]: Xt = Xt.copy()

In [17]: Xt.iloc[0,0]=6

In [18]: Xt
Out[18]:
   A  B
0  6  2
2  7  3
1  5  5

In [19]: X
Out[19]:
   A   B
0  2   2     # <--- NOTE: the value in the original DF has NOT been changed
1  5   5
2  7   3
3  8  51
4  9   5

或者，您可以使用 numpy.split(...)方法

这篇关于 pandas 在train_test_split之后显示SettingWithCopyWarning的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！