How to make string get elements from an array based on the combobox array

I miss something and I will appreciate your help I have this array for a combobox

String array [] = {"aa", "bb", "cc"};

and I have this for loop to run all over the array

for(String s: array) {
if(s.equals(array[0]) {
   do something
  }
}

Now what I need is that, I need the "do something" to happen to each element in the array only when the element is selected by the combobox, my array is so long and I can't write if statement for each element in the array.

what I want is something like that

for(String s : array) { 
  if(s equals the array elements) {
      substring the first index of each element
      print s
      so result let's say will be like this
      a ----> if only element a is selected
      b ----> if only element b is seleceted
      etc ...
  }

}

Thank you in advance