How to simulate 'except' for string lists in for loop in Java?

Question

I have a list of strings ( partList ) which is a fraction part of another list of strings ( completeList ) and i want to process an object (through processObj() ) within a for loop in a way that the current element of the partList will be retracted from the completeList: when the current iteration is on an element of partList then the processing of the object will involve that element and the rest of elements from completeList i do it like so for now:

        for (String el: partList) {
            completeList.remove(el);
            //process the target object using as parameters el and the rest of the complete list except el...
            processObj(el,completeList);
            completeList.add(el);
        }

Is it the right way of doing it? Thanks for the enlightenment.

Answer 1

I'm not sure the purpose of removing then adding back to the same list, but you can use a Predicate to accept and process certain values.

Predicate<String> accept = (s) -> {
  return true;  // accepts all strings; you could use partList.contains(s) here, or !s.equals(el)
}
completeList.stream()
    .filter(accept.negate()) // Inverse the predicate to implement "except" 
    .forEach(processObj); 

Replace forEach with map if you want to modify the stream values, then you can collect() to get data back to a list.