How to match a ListBuffer's items to an Array's item in Scala?-CodePudding

So I have a use case where I have a ListBuffer of Strings [let's call it 'A'], and an array of Strings (or if it's easier let's take it as another ListBuffer) [let's call it 'B']. There are no duplicate of items in either A or B

Now I want to do this:

if (A.isEmpty){
     // do something
}
else if (every item of 'A' must be present in 'B'){
     // do something else
}
else{
     // do something different
}

This should take care of edge cases like:

B is empty ['else if' check should fail]
len(A) < len(B), but items of A are there in B ['else if' check should pass]
others...

How should I write the else if block in this case?

CodePudding user response：

Slow version

A.forall(B.contains)

Faster version

val bSet = B.to(Set)
A.forall(bSet.contains)

And a version from @jwvh that is probably somewhere in the middle

a.diff(b).isEmpty