Difference of two character vectors with substring

Question

I have two lists:

a <- c(\"da\", \"ba\", \"cs\", \"dd\", \"ek\")
b <- c(\"zyc\", \"ulk\", \"mae\", \"csh\", \"ddi\", \"dada\")

I want

Answer 1

We can paste the 'a' elements to a single string with | as the delimiter, use that as pattern in grepl, negate (!) to subset 'b'.

 b[!grepl(paste(a, collapse="|"), b)]