我想知道，一列中的字符串是否存在于一列范围中。搜索列可以包含多个字符串，用“，“分隔。我称它们为“搜索项”。我不关心是否找到一个或多个项，但我需要知道是否存在重复项。下面是一些模拟数据

df <- data.frame(
  a=c("a","b","c, d","d"), 
  b=c(NA, "k", NA,"k"), 
  c=c("c1","c2","c3","c4, c5"), 
  search_terms=c("a",NA,"c, a","a, c5"))
df

     a    b      c search_terms
1    a <NA>     c1            a
2    b    k     c2         <NA>
3 c, d <NA>     c3         c, a
4    d    k c4, c5        a, c5

我希望的结果是：

test
1 search term found in a_c
2 <NA>
3 search term found in a_c
4 search term found in a_c

解释者：
1.检索词“a”位于a列
1.没有检索词
1.检索词“c”在a列
1.检索词“c5”在c列
所以可以在搜索列的所有子字符串中搜索一个字符串。下面的代码正确地识别了第4行中的“c5”。但是我没有进行行匹配。

df %>% mutate(test=ifelse(sapply(strsplit(df$search_terms, ", "), 
                                 function(x) {any(x == "c5")}),
                          "search term found in a_c",NA)) %>%
  select(test)

                test
1               <NA>
2               <NA>
3               <NA>
4 search term found in a_c

我进一步设法检查行的存在性，但不是当输入是字符串列表时。这段代码正确地识别了第一个匹配，但没有识别第三个或第四个匹配。

df %>% tidyr::unite(a_c,a:c, na.rm = TRUE, remove=F,sep = ',') %>% 
  mutate(test=ifelse(mapply(grepl, search_terms,a_c),
                      "search term found in a_c",NA))%>%
  select(test)

                      test
1 search term found in a_c
2                     <NA>
3                     <NA>
4                     <NA>

我希望沿着下面的代码行将两者结合起来，但是grepl只取了第一个元素，所以它正确地识别了第一个和第三个匹配项，但是没有识别出第4行中的匹配项，那么为什么any-命令不在这里工作，而是在第一行代码中工作呢？

df %>% tidyr::unite(a_c,a:c, na.rm = TRUE, remove=F,sep = ',') %>% 
  mutate(test=ifelse(apply(.,1,function(x) {
    sapply(strsplit(x["search_terms"],", "), function(y) {
      any(grepl(y,x["a_c"]))
      })
    }),"search_term in a_c",NA)
    ) %>%
  select(test)

                test
1 search term found in a_c
2               <NA>
3 search term found in a_c
4               <NA>

Warning messages:
1: Problem while computing `test = ifelse(...)`.
ℹ argument 'pattern' has length > 1 and only the first element will be used 
2: Problem while computing `test = ifelse(...)`.
ℹ argument 'pattern' has length > 1 and only the first element will be used