Java将未知项目添加到arraylist

Question

hi I have a quick question.

I'm having a problem with adding an item from an input.txt file to a new list.

I have a file with 28 items, with names and numbers, 27 of them are part of the categories and lists I've created. But then there is another one that should be treated and included in a new category called "unknown items", this one should include any item that is there or might be added not belonging to those lists, including misspells.

Anyway, I created ArrayLists for my categories and for my lists. This my code for those and it works fine:

for(Items i : list) {
        for(String name: cat1) {
            if(i.name.equalsIgnoreCase(name))
                lista1.add(i);
        }

but then when I try to to make the same for the unknown items list, it doesn't work, right now what I get is the exact opposite of what I need and it's the closest I've been from sorting it out, it's including 27 items and excluding the one I need and when I try to invert it, it just gets screwed up and I just can't figure out what I'm doing wrong, this is what I have:

next:
        for(String name: catAll){
            if(!i.name.equalsIgnoreCase(name)) continue next;

                listUnknow.add(i);
        }

If anyone could help me out I'd appreciate it.

Thanks

Answer 1

You're looking for something like this:

for(Items i : list) {
    boolean unknown = true;
    for(String name: cat1) {
        if(i.name.equalsIgnoreCase(name)) {
            lista1.add(i);
            unknown = false;
            break;
        }
    }
    if(unknown) {
        listUnknown.add(i);
    }
}

The problem with your code is that inverting doesn't work like you think it does. If your cat1 contains "a", "b" and your current item is a "b", then the first check will return true. After all, !"b".equalsIgnoreCase("a") is true. You need to check all items in cat1 before you can say it is unknown.

Answer 2

Don't know what p & i is in your second snippet but it starts the loop on every continue... maybe try without the label (to skip adding)?

for(String name: catAll){
        if(!i.name.equalsIgnoreCase(name)){
          continue;
        }

        listUnknow.add(p);
    }