Comparing an Arraylist in a List with other Arraylists within the same list

Question

I have been trying to no avail to find a solution to this thing i am trying to do. What i am trying to do is to check if the String superConcept is equal to the first element of a line within the kb, and if so, it is checked if any of the remaining Arraylists in the list contain the same first element.

public static List<ArrayList<String>> kb = new ArrayList<>();

for(ArrayList<String> line : kb){
    if(superConcept.equals(line.get(0))){
        //to check if there are any other lines within the kb that contain the same first element (line.get(0))
    }
}

So you want to figure out which arraylists contain superConcept as their first element? — cegredev
– cegredev, Commented Apr 17, 2020 at 12:27

cegredev · Accepted Answer · 2020-04-17 12:39:35Z

2

Do it like this:

List<ArrayList<String>> targetLists = new ArrayList<>();

for (ArrayList<String> list : kb)
    if (list.size() > 0 && list.get(0).equals(superConcept))
        targetLists.add(list);

edited Apr 17, 2020 at 12:39

answered Apr 17, 2020 at 12:34

cegredev

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2 Comments

Mr Mosby Over a year ago

how would i go about clearing everything in targetList after i am done with the iteration, so that i would have targetLists fresh when the next iteration starts?

cegredev Over a year ago

What iteration? Just create a new one everytime you call this piece of code, or, if you want to make it a global variable, call targetLists.clear() before the loop.

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