Check whether two vectors contain the same (unordered) elements in R

Question

I\'d like to check whether two vectors contain the same elements, even if they\'re not ordered the same. For example, the function (let\'s call it SameElements)

Answer 1

Basically your problem can be outlined in those steps :

if not same unique values: return FALSE
else if same Frequencies: return TRUE
    else return True

In proper R code :

SameElements = function(v1, v2)
{
  tab1 = table(v1) ; tab2 = table(v2)
  if( !all(names(tab1) == names(tab2)) ) return(FALSE) # Same unique values test
  return(all(tab1==tab2)) # Same frequencies test
}

Some examples :

v1 = c(1, 2, 3)
v2 = c(3, 2, 1)
SameElements(v1, v2) # TRUE as both uniqueness and frequencies test are verified

v1 = c(1,1, 2,3)
v2  =c(3,2,1)
S

ameElements(v1, v2) # FALSE as frequencies test is violated

PS : i) You can replace !all() by any()
~~~ii) To speed up the code you can quickly return FALSE when the two vectors don't
~~~have the same length, thus avoiding frequencies computation.