r语言 - 根据列条件将字符串粘贴到值

Question

我有一个数据框架，看起来像这样:

df <- tibble::tribble(
~subcateg, ~names, ~categ, ~names2,
"A00", "Kidney failure", "A00", "Kidney failure",
"A001", "Kidney failure reason1", "A00", "Kidney failure",
"A002", "Kidney failure reason2","A00", "Kidney failure",
"A003", "Kidney failure reason3","A00", "Kidney failure",
"B00", "Heart failure", "B00", "Heart failure",
"B001", "Heart failure reason1",  "B00", "Heart failure",
"B002", "Heart failure reason2",  "B00", "Heart failure",
"B003", "Heart failure reason3",  "B00", "Heart failure",
"C00", "Lung failure", "C00", "Lung failure",
"C001", "Lung failure reason1",  "C00", "Lung failure",
"C002", "Lung failure reason2",  "C00", "Lung failure",
"C003", "Lung failure reason3",  "C00", "Lung failure",
)

我需要添加一个"X"到只有3chr的列1的值。这是列subcateg=categ的值，所以它应该是这样的:

df <- tibble::tribble(
~subcateg, ~names, ~categ, ~names2,
"A00X", "Kidney failure", "A00", "Kidney failure",
"A001", "Kidney failure reason1", "A00", "Kidney failure",
"A002", "Kidney failure reason2","A00", "Kidney failure",
"A003", "Kidney failure reason3","A00", "Kidney failure",
"B00X", "Heart failure", "B00", "Heart failure",
"B001", "Heart failure reason1",  "B00", "Heart failure",
"B002", "Heart failure reason2",  "B00", "Heart failure",
"B003", "Heart failure reason3",  "B00", "Heart failure",
"C00X", "Lung failure", "C00", "Lung failure",
"C001", "Lung failure reason1",  "C00", "Lung failure",
"C002", "Lung failure reason2",  "C00", "Lung failure",
"C003", "Lung failure reason3",  "C00", "Lung failure",
)

我试过这样做:

df %>%
filter(subcateg = categ)  %>%
paste0(df$subcateg, "X")

但它不起作用。什么好主意吗?

谢谢!

Answer 1

可以在ifelse语句中使用nchar:

library(dplyr)
df %>% 
mutate(subcateg= ifelse(nchar(subcateg)==3, paste0(subcateg, "X"), subcateg))

subcateg names                  categ names2        
<chr>    <chr>                  <chr> <chr>         
1 A00X     Kidney failure         A00   Kidney failure
2 A001     Kidney failure reason1 A00   Kidney failure
3 A002     Kidney failure reason2 A00   Kidney failure
4 A003     Kidney failure reason3 A00   Kidney failure
5 B00X     Heart failure          B00   Heart failure 
6 B001     Heart failure reason1  B00   Heart failure 
7 B002     Heart failure reason2  B00   Heart failure 
8 B003     Heart failure reason3  B00   Heart failure 
9 C00X     Lung failure           C00   Lung failure  
10 C001     Lung failure reason1   C00   Lung failure  
11 C002     Lung failure reason2   C00   Lung failure  
12 C003     Lung failure reason3   C00   Lung failure 

Answer 2

我们可以使用case_when创建一个基于'subcateg'中nchar值3到paste(str_c) 'subcateg'末尾的'X'的逻辑向量

library(dplyr)
library(stringr)
df %>% 
mutate(subcateg = case_when(nchar(subcateg) == 3 ~ 
str_c(subcateg, 'X'), TRUE ~ subcateg))

-ouptut

# A tibble: 12 × 4
subcateg names                  categ names2        
<chr>    <chr>                  <chr> <chr>         
1 A00X     Kidney failure         A00   Kidney failure
2 A001     Kidney failure reason1 A00   Kidney failure
3 A002     Kidney failure reason2 A00   Kidney failure
4 A003     Kidney failure reason3 A00   Kidney failure
5 B00X     Heart failure          B00   Heart failure 
6 B001     Heart failure reason1  B00   Heart failure 
7 B002     Heart failure reason2  B00   Heart failure 
8 B003     Heart failure reason3  B00   Heart failure 
9 C00X     Lung failure           C00   Lung failure  
10 C001     Lung failure reason1   C00   Lung failure  
11 C002     Lung failure reason2   C00   Lung failure  
12 C003     Lung failure reason3   C00   Lung failure