行上应用的几何均值 [英] Geometric mean applied on row

问题描述

我以这个数据框为例:

Col1       Col2       Col3       Col4
   1          2          3        2.2

我想添加一个名为"Gmean"的第4列，该列计算每行的前3列的几何平均值.

I would like to to add a 4th column called 'Gmean' that calculate the geometric mean of the first 3 columns on each row.

如何完成它?

谢谢！

推荐答案

一种方法是使用

One way would be with Scipy's geometric mean function -

from scipy.stats.mstats import gmean

df['Gmean'] = gmean(df.iloc[:,:3],axis=1)

formula of geometric mean 本身的另一种方式-

Another way with the formula of geometric mean itself -

df['Gmean'] = np.power(df.iloc[:,:3].prod(axis=1),1.0/3)

如果正好有3列，则只需使用df而不是df.iloc[:,:3].另外，如果您正在寻找性能，则可能要使用df.values或df.iloc[:,:3].values处理基础数组数据.

If there are exactly 3 columns, just use df instead of df.iloc[:,:3]. Also, if you are looking for performance, you might want to work with the underlying array data with df.values or df.iloc[:,:3].values.

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