如何扩展“摘要"功能以包括 sd、峰度和偏斜? [英] How to extend the 'summary' function to include sd, kurtosis and skew?

问题描述

R 的 summary 函数在数据帧上工作得非常好，例如:

R's summary function works really well on a dataframe, giving, for example:

> summary(fred)
   sum.count          count              sum              value      
 Min.   : 1.000   Min.   :    1.0   Min.   :      1   Min.   : 0.00  
 1st Qu.: 1.000   1st Qu.:    6.0   1st Qu.:      7   1st Qu.:35.82  
 Median : 1.067   Median :    9.0   Median :     10   Median :42.17  
 Mean   : 1.238   Mean   :  497.1   Mean   :   6120   Mean   :43.44  
 3rd Qu.: 1.200   3rd Qu.:   35.0   3rd Qu.:     40   3rd Qu.:51.31  
 Max.   :40.687   Max.   :64425.0   Max.   :2621278   Max.   :75.95

我想要做的是修改函数，以便在均值"之后给出标准差、峰态和偏斜的条目.

What I'd like to do is modify the function so it also gives, after 'Mean', an entry for the standard deviation, the kurtosis and the skew.

这样做的最佳方法是什么?我对此进行了一些研究，添加带有方法的函数对我不起作用:

What's the best way to do this? I've researched this a bit, and adding a function with a method doesn't work for me:

> summary.class <- function(x)
{
  return(sd(x))
}

上面的只是被忽略了.我想我需要了解如何定义所有要返回的类.

The above is just ignored. I suppose that I need to understand how to define all classes to return.

推荐答案

如何使用 psych 包中已有的解决方案?

How about using already existing solutions from the psych package?

my.dat <- cbind(norm = rnorm(100), pois = rpois(n = 100, 10))

library(psych)
describe(my.dat)
#    vars   n  mean   sd median trimmed  mad   min   max range  skew kurtosis   se
# norm  1 100 -0.02 0.98  -0.09   -0.06 0.86 -3.25  2.81  6.06  0.13     0.74 0.10
# pois  2 100  9.91 3.30  10.00    9.95 4.45  3.00 17.00 14.00 -0.07    -0.75 0.33

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