根据R中的其他变量创建新变量
根据R中的其他变量创建新变量
提问于 2022-05-29 12:27:05
使用R，我试图创建一个变量，基于数据框架中的3个现有变量。示例：
n <- 20
dat <- data.frame(id=1:n,
group=rep(LETTERS[1:5]),
type=factor(paste("type", 1:2)))新变量“模型”的值应基于以下3项：
If "type" = 1 then "model"= apple
If "type" = 2 and "group" A or B, then "model"=cherry
If "type" = 2 and "group" C and "id" 1-4, then"model"= strawberry
If "type" = 2 and "group" C and "id" 5-8, then"model"= melon
If "type" = 2 and "group" C and "id" >9, then "model"=pineapple我试过了ifelse，但是我很难适应这些条件。
如何解决这个问题？
回答 2
Stack Overflow用户
发布于 2022-05-29 12:39:02
您可以从tidyverse中使用case_when：
library(tidyverse)
n <- 20
dat <- data.frame(id=1:n,
group=rep(LETTERS[1:5]),
type=factor(paste("type", 1:2)))
dat %>%
mutate(
model = case_when(
type == "type 1" ~ "apple",
type == "type 2" & group %in% c("A", "B") ~ "cherry",
type == "type 2" & group == "C" & id %in% c(1:4) ~ "strawberry",
type == "type 2" & group == "C" & id %in% c(5:8) ~ "melon",
type == "type 2" & group == "C" & id >9 ~ "pineapple"
)
)Stack Overflow用户
发布于 2022-05-29 12:46:09
嵌套ifelse选项：
dat$color <- with(dat, ifelse(type == "type 1", "apple",
ifelse(type == "type 2" & group %in% c("A", "B"), "cherry",
ifelse(type == "type 2" & group == "C" & id %in% (1:4), "strawberry",
ifelse(type == "type 2" & group == "C" & id %in% (5:8), "melon",
ifelse(type == "type 2" & group == "C" & id >= 9, "pineapple", NA))))))输出：
id group type color
1 1 A type 1 apple
2 2 B type 2 cherry
3 3 C type 1 apple
4 4 D type 2 <NA>
5 5 E type 1 apple
6 6 A type 2 cherry
7 7 B type 1 apple
8 8 C type 2 melon
9 9 D type 1 apple
10 10 E type 2 <NA>
11 11 A type 1 apple
12 12 B type 2 cherry
13 13 C type 1 apple
14 14 D type 2 <NA>
15 15 E type 1 apple
16 16 A type 2 cherry
17 17 B type 1 apple
18 18 C type 2 pineapple
19 19 D type 1 apple
20 20 E type 2 <NA>页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/72423614
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