按R中的子组百分比汇总 [英] Summarizing by subgroup percentage in R

问题描述

我有一个像这样的数据集:

I have a dataset like this:

df = data.frame(group = c(rep('A',4), rep('B',3)),
                subgroup = c('a', 'b', 'c', 'd', 'a', 'b', 'c'),
                value = c(1,4,2,1,1,2,3))


group | subgroup | value
------------------------
  A   |    a     |  1
  A   |    b     |  4
  A   |    c     |  2
  A   |    d     |  1
  B   |    a     |  1
  B   |    b     |  2
  B   |    c     |  3

我想要的是获取每个组中每个子组的值的百分比，即输出应为:

What I want is to get the percentage of the values of each subgroup within each group, i.e. the output should be:

group | subgroup | percent
------------------------
  A   |    a     |  0.125
  A   |    b     |  0.500
  A   |    c     |  0.250
  A   |    d     |  0.125
  B   |    a     |  0.167
  B   |    b     |  0.333
  B   |    c     |  0.500

A组，A组的示例:值是1，整个A组的总和是8(a = 1，b = 4，c = 2，d = 1)-因此1/8 = 0.125

Example for group A, subgroup A: the value was 1, the sum of the whole group A is 8 (a=1, b=4, c=2, d=1) - hence 1/8 = 0.125

到目前为止，我只发现了非常简单的聚合，例如

So far I've only found fairly simple aggregates like this, but I cannot figure out how to do the "divide by a sum within a subgroup" part.

推荐答案

根据您的评论，如果子组是唯一的，则可以

Per your comment, if the subgroups are unique you can do

library(dplyr)
group_by(df, group) %>% mutate(percent = value/sum(value))
#   group subgroup value   percent
# 1     A        a     1 0.1250000
# 2     A        b     4 0.5000000
# 3     A        c     2 0.2500000
# 4     A        d     1 0.1250000
# 5     B        a     1 0.1666667
# 6     B        b     2 0.3333333
# 7     B        c     3 0.5000000

或者要删除value列并同时添加percent列，请使用transmute

Or to remove the value column and add the percent column at the same time, use transmute

group_by(df, group) %>% transmute(subgroup, percent = value/sum(value))
#   group subgroup   percent
# 1     A        a 0.1250000
# 2     A        b 0.5000000
# 3     A        c 0.2500000
# 4     A        d 0.1250000
# 5     B        a 0.1666667
# 6     B        b 0.3333333
# 7     B        c 0.5000000

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