How to subtract a complete character vector with repeated characters from the other vector in R

Question

I want to subtract y from x, which means remove one \"A\", three \"B\" and one \"E\" from x, so xNew will be c(\"A\", \"C\", \"A\",\"B\",\"D\"). It

Answer 1

You can use the function pmatch:

x[-pmatch(y,x)]
#[1] "A" "C" "A" "B" "D"

Edit
If your data can be strings of more than 1 character, here is an option to get what you want:

xNew <- unlist(sapply(x[!duplicated(x)], 
                      function(item, tab1, tab2) {
                          rep(item,
                              tab1[item] - ifelse(item %in% names(tab2), tab2[item], 0))
                       }, tab1=table(x), tab2=table(y)))

Example

x <- c("AB","BA","C","CA","B","B","B","B","D","E")
y <- c("A","B","B","B","E")
xNew
#  AB   BA    C   CA    B    D 
#"AB" "BA"  "C" "CA"  "B"  "D"