我有一个pandas DataFrame,包含一些随时间推移的传感器读数,如下所示:
diode1 diode2 diode3 diode4
Time
0.530 7 0 10 16
1.218 17 7 14 19
1.895 13 8 16 17
2.570 8 2 16 17
3.240 14 8 17 19
3.910 13 6 17 18
4.594 13 5 16 19
5.265 9 0 12 16
5.948 12 3 16 17
6.632 10 2 15 17
# List of the averages for the test.
averages = [df[key].describe()['mean'] for key in df]
indexes = df.index.tolist()
indexes.append('mean')
df.reindex(indexes)
# Adding the mean row to the bottom of the DataFrame
i = 0
for key in df:
df.set_value('mean', key, averages[i])
i += 1
这给了我想要的结果,这是一个像这样的DataFrame:
diode1 diode2 diode3 diode4
Time
0.53 7.0 0.0 10.0 16.0
1.218 17.0 7.0 14.0 19.0
1.895 13.0 8.0 16.0 17.0
2.57 8.0 2.0 16.0 17.0
3.24 14.0 8.0 17.0 19.0
3.91 13.0 6.0 17.0 18.0
4.594 13.0 5.0 16.0 19.0
5.265 9.0 0.0 12.0 16.0
5.948 12.0 3.0 16.0 17.0
6.632 10.0 2.0 15.0 17.0
mean 11.6 4.1 14.9 17.5
但是,我确信这不是添加行的最有效方法.我尝试使用append作为熊猫系列保存的方法,但结果是这样的:
diode1 diode2 diode3 diode4 mean
0 7.0 0.0 10.0 14.0 NaN
1 9.0 0.0 10.0 15.0 NaN
2 10.0 5.0 14.0 20.0 NaN
3 6.0 0.0 7.0 14.0 NaN
4 7.0 0.0 10.0 15.0 NaN
5 7.0 0.0 8.0 14.0 NaN
6 7.0 0.0 11.0 14.0 NaN
7 7.0 0.0 2.0 11.0 NaN
8 2.0 0.0 4.0 12.0 NaN
9 4.0 0.0 0.0 6.0 NaN
10 NaN NaN NaN NaN [11.6, 4.1, 14.9, 17.5]
我想知道是否有更有效的方法来添加一个索引’mean’的行和每个列的平均值到pandas DataFrame的底部.
解决方法:
使用loc
表示setting with enlargement:
df.loc['mean'] = df.mean()
结果输出:
diode1 diode2 diode3 diode4
Time
0.53 7.0 0.0 10.0 16.0
1.218 17.0 7.0 14.0 19.0
1.895 13.0 8.0 16.0 17.0
2.57 8.0 2.0 16.0 17.0
3.24 14.0 8.0 17.0 19.0
3.91 13.0 6.0 17.0 18.0
4.594 13.0 5.0 16.0 19.0
5.265 9.0 0.0 12.0 16.0
5.948 12.0 3.0 16.0 17.0
6.632 10.0 2.0 15.0 17.0
mean 11.6 4.1 14.9 17.5