How could I check that how many elements of x is inside y?

Suppose I have

x = [2,7,8,11];

and

y = [1,2,4,5,7,8,9,12,15,21,27]

How could I check that how many elements of x is inside y?

Answer 1

[Stephen23]

You can use ismember:

>> x = [2,7,8,11];
>> y = [1,2,4,5,7,8,9,12,15,21,27];
>> ismember(x,y)
ans =
   1   1   1   0

>> sum(ismember(x,y))
ans =  3