tidyverse：将字符串拆分为 data.frame 作为行

Question

我想将基于\n 的字符串拆分为data.frame 的行。下面给出的代码不能按要求工作。任何提示。

library(tidyverse)
Test <- "ASD 7\nDEF \n This"

library(stringr)
str_split(string = Test, pattern = "\n")
[[1]]
[1] "ASD 7" "DEF "  " This
    
tb <- 
  as_tibble(Test) %>% 
  set_names("Test")

tb %>% 
  str_split(string = Test, pattern = "\n")
[[1]]
[1] NA

Warning message:
In stri_split_regex(string, pattern, n = n, simplify = simplify,  :
  NAs introduced by coercion

所需输出

ASD 7
DEF
This

Answer 1

str_split 旨在处理原子向量而不是数据集。它没有 data 的参数，因此它只能像这样工作

str_split(tb$Test, '\n')

[[1]]
[1] "ASD 7" "DEF "  " This"

或

> tb %>%
+   mutate(chr_list = str_split(Test, '\n'))
# A tibble: 1 x 2
  Test                 chr_list 
  <chr>                <list>   
1 "ASD 7\nDEF \n This" <chr [3]>

另外，如果你喜欢在数据库中做，你可以这样做tidyr::separate或tidyr::separate_rows()这样

tb %>%
  separate_rows(Test, sep = '\n')

# A tibble: 3 x 1
  Test   
  <chr>  
1 "ASD 7"
2 "DEF " 
3 " This"

或

tb %>%
  separate(Test, into = c('A', 'B', 'C'), sep = '\n')

# A tibble: 1 x 3
  A     B      C      
  <chr> <chr>  <chr>  
1 ASD 7 "DEF " " This"

---

PS：如果你也想去掉空格，可以使用'\\s*\n+\\s*'作为分隔符

tb %>%
  transmute(text_data = map(str_split(Test, '\n'), ~ str_trim(.x))) %>%
  unnest_longer(text_data)

# A tibble: 3 x 1
  text_data
  <chr>    
1 ASD 7    
2 DEF      
3 This

或

tb %>%
  separate_rows(Test, sep = "\\s*\n+\\s*")

# A tibble: 3 x 1
  Test 
  <chr>
1 ASD 7
2 DEF  
3 This