Extracting unique numbers from string in R

For the second answer, you can use gsub to remove everything from the string that's not a number, then split the string as follows:

unique(as.numeric(unlist(strsplit(gsub("[^0-9]", "", unlist(ll)), ""))))
# [1] 7 6 1 5 2

For the first answer, similarly using strsplit,

unique(na.omit(as.numeric(unlist(strsplit(unlist(ll), "[^0-9]+")))))
# [1]   7 667  11   5   2

PS: don't name your variable list (as there's an inbuilt function list). I've named your data as ll.

Here is yet another answer, this one using gregexpr to find the numbers, and regmatches to extract them:

l <- c("djud7+dg[a]hs667", "7fd*hac11(5)", "2tu,g7gka5")

temp1 <- gregexpr("[0-9]", l)   # Individual digits
temp2 <- gregexpr("[0-9]+", l)  # Numbers with any number of digits

as.numeric(unique(unlist(regmatches(l, temp1))))
# [1] 7 6 1 5 2
as.numeric(unique(unlist(regmatches(l, temp2))))
# [1]   7 667  11   5   2