通过 R 中每个组的平均值逐组减去值 [英] Subtracting values group-wise by the average of each group in R

问题描述

我正在尝试从每个组的值中减去组均值.

I am trying to subtract group means from each group's values.

例如:

> x <- data.frame('gene' = c('A','A','A','B','B','C','C','C'),'value' = c(32.3,31,30.5,25,22.1,20.5,21.2,19.8))
> x
  gene value
1    A  32.3
2    A  31.0
3    A  30.5
4    B  25.0
5    B  22.1
6    C  20.5
7    C  21.2
8    C  19.8

我能找到组的意思是:

> aggregate(x[,2],list(x$gene),mean)
  Group.1        x
1       A 31.26667
2       B 23.55000
3       C 20.50000

如何用对应的组均值减去 x 中的值"?我想要的结果如下:

How do I subtract the "value" in x by the corresponding group mean? My desire result is as follow:

   gene value-group.mean
1    A  1.03333
2    A  -0.26667
3    A  -0.76667
4    B  1.45
5    B  -1.45
6    C  0
7    C  0.7
8    C  -0.7

我如何在 R 中做到这一点?

How can I do it in R?

谢谢.

推荐答案

使用库dplyr，你可以:

library(dplyr)
x %>%
  group_by(gene) %>%
  mutate_all(funs(.-mean(.)))

# A tibble: 8 x 2
# Groups:   gene [3]
  gene   value
  <fct>  <dbl>
1 A      1.03 
2 A     -0.267
3 A     -0.767
4 B      1.45 
5 B     -1.45 
6 C      0    
7 C      0.700
8 C     -0.700

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