在R中按组有条件地创建变量(写函数) [英] create variable conditionally by group in R (write function)

问题描述

我想按组创建一个变量，条件是在单个级别上以现有变量为条件.每个人都有一个离群变量1，2，3.我想按组创建一个新变量，以便每当该组中至少有一个人的离群变量= 2时，新的var = 2；因此，当该组中至少有一个个体的离群变量= 3时，新的var =3.

I want to create a variable by group conditioned on existing variable on individual level. Each individual has a outlier variable 1, 2, 3. I want to create a new variable by group so that the new var = 2 whenever there is at least one individual in that group whose outlier variable = 2; and the new var = 3 whenever there is at least one individual in that group whose outlier variable = 3.

数据看起来像这样

grpid id outlier
1     1   1
1     2   1
1     3   2
2     4   1
2     5   3
2     6   1
3     7   1
3     8   1
3     9   1

理想的输出

grpid id outlier  goutlier
1     1   1       2
1     2   1       2
1     3   2       2
2     4   1       3
2     5   3       3
2     6   1       3
3     7   1       1
3     8   1       1
3     9   1       1

有什么建议吗?

谢谢！

推荐答案

使用dplyr

library(dplyr)
df <- read.table(header = TRUE,sep = ",",
                 text = "grpid,id,outlier
1,1,1
1,2,1
1,3,2
2,4,1
2,5,3
2,6,1
3,7,1
3,8,1
3,9,1")

df %>% group_by(grpid) %>% mutate(goutlier = max(outlier))

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