根据列条件将字符串粘贴到值答案

【问题标题】：paste string to value based on column condition根据列条件将字符串粘贴到值
【发布时间】：2021-11-26 00:17:52
【问题描述】：

我有一个如下所示的数据框：

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",
)

我需要在只有 3 个字符的第 1 列的值中添加一个“X”。这是列 subcateg=categ 的值，因此应该如下所示：

    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",
)

我尝试过这样的事情：

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

但它不起作用。有什么想法吗？

谢谢！

【问题讨论】：

标签： r string character paste

【解决方案1】：

我们可以在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

【讨论】：

【解决方案2】：

我们可以使用case_when 来创建一个基于“子类别”中nchar 值3 到“子类别”末尾的paste (str_c) 的逻辑向量

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

-输出

# 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

【讨论】：