R 字符数据的集合操作（整数字符串）

有人知道如何设计一种快速的方法来计算两列的相对重叠吗？我想知道集合“b”中有多少个“a”元素。理想情况下，会生成一列“c”，用于存储每行的这些比较值。我真的很坚持这一点

b <- c("20", "1, 8, 19, 20, 22, 23, 28, 34, 41", 
       "3, 8, 10, 11, 18, 20, 26, 37", 
       "1, 3, 6, 18, 21, 35", "NA", "1, 21, 33", "14, 37",
       "4, 14, 18, 23, 33, 37, 40", "14", 
       "4, 14, 20, 23, 33, 37, 40", 
       "2, 3, 5, 7, 8, 10, 14, 16, 18, 23, 25, 34, 40", 
       "6, 8, 10, 14, 19, 29, 33, 35, 36, 39, 41",
       "1, 20", "1, 28, 36", "14", 
       "1, 6, 33, 12, 39", "28", 
       "1, 6, 11, 13, 18, 19, 21, 28, 33, 35, 36, 39", 
       "35, 40", "20", "20, 38", "6, 8, 19, 22, 29, 32, 33, 34, 40",
       "1, 10, 21, 25, 33, 35, 36, 39, 40", "36")

a <- c("14", "10", "8, 39", "26, 39", "14, 20", "33, 36", "14", 
       "NA", "8, 39", "33, 36", "8, 39", "1, 36",  "10", "28, 33",
       "14, 20", "33, 40", "28, 34", "1, 36", 
       "8, 39",  "20", "14, 20", "29, 33", "36", "14")

df <- data.frame(a, b)

df$a <- as.character(df$a)
df$b <- as.character(df$b)

---

我不明白为什么需要将

转换为.numeric

。就是那个给你警告的。“NA”在数据帧中被视为一个字符值，这是一个无法转换为数字的字符值

请注意，警告不是错误，因此您的代码实际上也适用于第5行（除非您预期为NA）

我会做以下几件事：

getCounts <- function(x,y){
  x <- strsplit(x,", ")[[1]]
  y <- strsplit(y,", ")[[1]]
  mean(y %in% x)
}
# gives
> getCounts(df$a[5],df$b[5])
[1] 0

getCounts <- function(x,y){
  x <- strsplit(x,", ")[[1]]
  y <- strsplit(y,", ")[[1]]
  mean(y %in% x)
}
# gives
> getCounts(df$a[5],df$b[5])
[1] 0

out <- mapply(getCounts,df$a, df$b)