用Rpply匹配R中的两个字符向量

Question

I want to match items from two character vectors, "A" and "B", two find out two things: 1) whether items from vector A appear in vector B (yes/no) and 2) which items from vector B do not appear in vector A?

The two vectors look like this:

A <- c("i", "u", "I", "U", "E", "V", "@", "{", "$", "#", "Q", "1", "2", "3", "4", "5", "6", "7", "8", "9")
B <- c("1", "1", "1", "1", "#", "$", "$", "1", "2", "2", "1", "d", "d", "i", "i", "i", "i", "1", "3", "2", "2", "F", "2", "2", "2", "5", "5", "5", "@", "5", "6", "5", "z", "z", "S", "S")

I can partially answer my first question with this function:

test_match <- function(item_vector_A, item_vector_B){
ifelse(item_vector_A == item_vector_B, print(1), print(0))
}

lapply(A, B, FUN = test_match) -> results

However, when I try this, I get a list of each comparison the function has made:

lapply(A, B, FUN = test_match) -> results
results
[[1]]
[1] 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[[2]]
[1] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[[3]]
[1] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
#etc.

How can I get just a simple list that indicates for each item in A whether it occurs in B (1) or not (0), like this:

1 0 0 0 0 0 1 0 1 1 0 1 1 1 0 1 1 0 0 0 

I have the same problem when I try to answer my second question:

test_non_match <- function(item_vector_A, item_vector_B){
ifelse(item_vector_B == item_vector_A, print("*match*"), print(item_vector_B))
}
lapply(A, B, FUN = test_non_match) -> results2
results2
[[1]]
[1] "1" "1" "1" "1" "#"  "$" "$" "1" "2" "2" "1" "d" "d" "*match*" "*match*" "*match*" "*match*" "1" "3" "2" "2" "F" "2" "2" "2" "5" "5" "5" "@" "5" "6" "5" "z" "z" "S" "S"      
[[2]]
[1] "1" "1" "1" "1" "#" "$" "$" "1" "2" "2" "1" "d" "d" "i" "i" "i" "i" "1" "3" "2" "2" "F" "2" "2" "2" "5" "5" "5" "@" "5" "6" "5" "z" "z" "S" "S"
[[3]]
[1] "1" "1" "1" "1" "#" "$" "$" "1" "2" "2" "1" "d" "d" "i" "i" "i" "i" "1" "3" "2" "2" "F" "2" "2" "2" "5" "5" "5" "@" "5" "6" "5" "z" "z" "S" "S"

It lists the whole vector, whereas I would like to have something like this:

[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] d
[1] d
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] F
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] *match*
[1] z
[1] z
[1] S
[1] S

Do I need to use another type of apply() function?

Answer 1

除了上面的替代方案，您可能需要查看％chin％，这是data.table包中％in％的更快版本：

ifelse (B %chin% A, "*match*", B)

Answer 2

You could just use %in% and test for A %in% B and !(B %in% A ) . To reproduce the output in your question:

as.numeric(A %in% B)
 [1] 1 0 0 0 0 0 1 0 1 1 0 1 1 1 0 1 1 0 0 0

and as suggested by Ferdinand.kraft:

ifelse (B %in% A, "*match*", B)
 [1] "*match*" "*match*" "*match*" "*match*" "*match*" "*match*" "*match*" "*match*" "*match*" "*match*" "*match*" "d"       "d"       "*match*" "*match*" "*match*" "*match*" "*match*" "*match*"
[20] "*match*" "*match*" "F"       "*match*" "*match*" "*match*" "*match*" "*match*"  "*match*" "*match*" "*match*" "*match*" "*match*" "z"       "z"       "S"       "S"