您可以将str_count Package 为sum：

items %>%
  mutate(Apple = sum(str_count(items, "Apple")),
         Pear = sum(str_count(items, "Pear")),
         Banana = sum(str_count(items, "Banana")))

                items Apple Pear Banana
1               Apple     3    2      1
2         Apple, Pear     3    2      1
3 Apple, Pear, Banana     3    2      1

特别是在您有多行和多个值的情况下-〉以下是一个解决方案，使用单独的行数并与cbind结合，最后通过填充NA进行透视：

library(dplyr)
library(tidyr)
df %>% 
  separate_rows(items, sep='\\,') %>% 
  count(items1 = trimws(items)) %>% 
  cbind(df) %>% 
  pivot_wider(names_from = items1, values_from = n) %>% 
  fill(-items, .direction = "downup")

items               Apple Banana  Pear
  <chr>               <int>  <int> <int>
1 Apple                   3      1     2
2 Apple, Pear             3      1     2
3 Apple, Pear, Banana     3      1     2

在感兴趣的单词上使用map-loop，并使用transmute返回一列，其中包含items列中单词的计数，并将输出绑定到原始数据

library(purrr)
library(dplyr)
 map_dfc(c("Apple", "Pear", "Banana"), ~ df1 %>%
    transmute(!! .x := sum(str_count(items, .x)))) %>%
    bind_cols(df1, .)

• 输出

items Apple Pear Banana
1               Apple     3    2      1
2         Apple, Pear     3    2      1
3 Apple, Pear, Banana     3    2      1

或者，另一种选择是拆分列"items"，使用mtabulate，并在获得colSums后对列进行cbind

library(qdapTools)
cbind(df1, as.list(colSums(mtabulate(strsplit(df1$items, ",\\s*")))))
                items Apple Banana Pear
1               Apple     3      1    2
2         Apple, Pear     3      1    2
3 Apple, Pear, Banana     3      1    2

您可以尝试以下操作，

library(tidyverse)

df <- structure(list(items = c(
    "Apple", "Apple, Pear", "Apple, Pear, Banana"
  )),
  row.names = c(NA,-3L),
  class = "data.frame")

total_count <- function(x, word) {
  paste0(x, collapse = ", ") %>% 
    stringr::str_count(word)
}
  
df %>%
  mutate(Apple = total_count(items, "Apple"),
         Pear = total_count(items, "Pear"),
         Banana = total_count(items, "Banana"))

#>                 items Apple Pear Banana
#> 1               Apple     3    2      1
#> 2         Apple, Pear     3    2      1
#> 3 Apple, Pear, Banana     3    2      1

创建于2023年1月4日，使用reprex v2.0.2