CODEWITHSUNDEEP
r
Amirul Islam
Amirul Islam

Reputation: 457

Subtract sets so that rest of the similar multiple elements are retained in the result

For example, I have 2 chairs and one table in set1 and 1 chair in set2. I want to subtract set2 from set1 and want the result as c("chair", "table")

set1 <- c("chair", "chair", "table")
set2 <- c("chair")

setdiff(set1, set2)

gives "table"

Upvotes: 3

Views: 1466

Answers (3)

Artem Sokolov
Artem Sokolov

Reputation: 13701

The package vecsets will perform set operations on vectors while retaining duplicates:

vecsets::vsetdiff( c("chair", "chair", "table"), c("chair") )
# [1] "chair" "table"

Upvotes: 0

Sotos
Sotos

Reputation: 51582

Another idea is to use make.unique to make the names unique, and then use %in% to create a logical vector and index the original one, i.e.

set1[!make.unique(set1) %in% make.unique(set2)]
#[1] "chair" "table"

Or make it a function,

f1 <- function(vec1, vec2){
    vec1[!make.unique(vec1) %in% make.unique(vec2)]
}

f1(set1, set2)

Upvotes: 1

Roland
Roland

Reputation: 132969

set1 <- c("chair", "chair", "table")
set2 <- c("chair")

levels <- union(set1, set2)

set1 <- factor(set1, levels = levels)
set2 <- factor(set2, levels = levels)

rep(levels, table(set1) - table(set2))
#[1] "chair" "table"

Upvotes: 3

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