how to mutate()-警告消息

Question

R的新手。

我正在尝试变异(Location2)，但它给了我警告消息：

#fix truncated values
DFnew %>%
  mutate(location2 = case_when(
    str_starts(Location, c("s", "S", "S.")) ~ "S. SJ @ Ashley Store", 
    str_starts(Location, c("p", "P")) ~ "Pleasanton @ Ranch 99",
    TRUE ~ NA_character_
  ))

Warning messages:
1: Problem with `mutate()` input `location2`.
i longer object length is not a multiple of shorter object length
i Input `location2` is `case_when(...)`. 
2: In stri_detect_regex(string, pattern, negate = negate, opts_regex = opts(pattern)) :
  longer object length is not a multiple of shorter object length

Answer 1

str_starts或任何stringr函数都接受正则表达式模式。如果你传递一个向量，它将匹配第一个模式和第一个值，第二个模式和第二个值，依此类推。

所以试试吧：

library(dplyr)
library(stringr)

DFnew <- DFnew %>%
          mutate(location2 = case_when(
                str_starts(Location, "s|S|S\\.") ~ "S. SJ @ Ashley Store", 
                str_starts(Location, "p|P") ~ "Pleasanton @ Ranch 99",
                TRUE ~ NA_character_
          ))

或者，您也可以使用带有ignore_case = TRUE的regex()函数来使正则表达式不区分大小写。

DFnew <- DFnew %>%
  mutate(location2 = case_when(
    str_starts(Location, regex("S\\.?", ignore_case = TRUE)) ~ "S. SJ @ Ashley Store", 
    str_starts(Location, regex("P", ignore_case = TRUE)) ~ "Pleasanton @ Ranch 99",
    TRUE ~ NA_character_
  ))