How to detect that a vector is subset of specific

问题:

I have two vectors (sets) like this:

first<-c(1,2,3,4,5)
second<-c(2,4,5)

how can I detect that whether second is subset of first or not? is there any function for this?

回答1:

Here's one way

> all(second %in% first)
[1] TRUE

回答2:

Here's another

setequal(intersect(first, second), second)
## [1] TRUE

Or

all(is.element(second, first))
## [1] TRUE

回答3:

If the order of the array elements matters, string conversion could help:

ord_match <- function(x,y){
    m <- c(0,grep(paste0(x,collapse=""),
                  paste0(y,collapse=""), fixed = T))
    return(as.logical(m)[length(m)])
}