CODEWITHSUNDEEP
rvectordiff
Jot eN
Jot eN

Reputation: 6396

Difference between two vectors in R

I have two vectors:

a <- c(1, 1, 3, 4, 5, 7, 9)
b <- c(2, 3, 4, 6, 8, 2)

I want to find the numbers in the second vector, which are not in the first vector:

dif <- c(2, 6, 8)

I've tried many different approaches (such as merge, different types of joins (dplyr package), setdiff, compare (compare package)), but I still can't find a way to do it.

Upvotes: 52

Views: 72504

Answers (4)

robertspierre
robertspierre

Reputation: 4341

if you want a visual comparison, you can use waldo

a <- c(1, 1, 3, 4, 5, 7, 9)
b <- c(2, 3, 4, 6, 8, 2)
waldo::compare(sort(a), sort(b))

enter image description here

Upvotes: 0

chara
chara

Reputation: 121

The exact question has been answered but if someone wants to find all elements not shared between two lists then this is the answer:

union(setdiff(a,b), setdiff(b,a))

Here 'a' and 'b' could be something like

a<-c(1,2,3,4,5)
b<-c(4,5,6,7,8)

Upvotes: 5

nico
nico

Reputation: 51640

An alternative way, instead of setdiff (which is probably preferrable), is to use %in%

unique(b[! b %in% a])
#[1] 2 6 8

Upvotes: 19

akrun
akrun

Reputation: 886948

You can use setdiff

setdiff(b,a)
#[1] 2 6 8

Upvotes: 78

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