JAVA - remove elements from a String array list

Question

I have an array list containing the following data;

[pagoda, hour, hour experience, pagoda, car, eatables, eatables water, walk, small, small garden, little, little hot, jungle, jungle beach, restaurant, ocean, local, room, morning, guy, pagoda small, small garden, hour experience, peaceful environment, view]

I want to check if an element in the arraylist contains value of another element, and if so remove the element which has the shorter length.

Eg:- look at hour, and hour experience in the arraylist above. I would need the method to remove hour element and keep only hour experience element.

This is what I wrote. But it doesn't work that well.

public void removeDuplicateKeywords(ArrayList<String> list){
        System.out.println(list);

        for(int i=0; i<list.size(); i++){
            String keyword = list.get(i);
            for(int j=i+1; j<list.size(); j++){
                if(keyword.equals(list.get(j))){
                    list.remove(j);
                }
                if(list.get(j).trim().contains(keyword.trim()) && list.get(j).length() > keyword.length()){

                    list.remove(i);
                }

            }

        }
        System.out.println(list);
    }

This will print

[pagoda, hour, hour experience, pagoda, car, eatables, eatables water, walk, small, small garden, little, little hot, jungle, jungle beach, restaurant, ocean, local, room, morning, guy, pagoda small, small garden, hour experience, peaceful environment, view]

[hour, hour experience, car, eatables water, walk, little, little hot, jungle beach, restaurant, ocean, local, room, morning, guy, pagoda small, small garden, peaceful environment, view]

Please help. Thanks in advance.

array = Stream.of(array).distinct().toArray(n -> new String[n]); — cybersoft
– cybersoft, Commented Mar 10, 2016 at 14:03
One issue you have is you are removing elements from the list while you are looping through it, without decrementing i or j. This means you will be skipping some of the items in the list. — forgivenson
– forgivenson, Commented Mar 10, 2016 at 14:09
Sort the list, then check for each element if the following element startsWith() the current one. If so, remove the current one. — BarrySW19
– BarrySW19, Commented Mar 10, 2016 at 14:22

Mena · Accepted Answer · 2016-03-10 14:12:23Z

2

Here's a way to achieve this with Java 8.

This solution is case-sensitive - it should be trivial to improve it to case-insensitive if so required.

// test list
List<String> duplicates = new ArrayList<>(
    Arrays.asList(
        new String[]{
            "pagoda", "hour", "hour experience", "pagoda", "car", "eatables", 
            "eatables water", "walk", "small", "small garden", "little", 
            "little hot", "jungle", "jungle beach", "restaurant", "ocean", 
            "local", "room", "morning", "guy", "pagoda small", "small garden", 
            "hour experience", "peaceful environment", "view"
        }
    )
);
// manipulating to Set with collections stream API
Set<String> noDuplicates = duplicates
    .stream()
    .filter(
        (s) -> duplicates.stream()
        // negative filter from original list
        .noneMatch(
            // condition: longer string that starts with current string
            (ss) -> ss.length() > s.length() && ss.startsWith(s)
        )
    )
    .collect(Collectors.toSet());

System.out.println(noDuplicates);

Output

[hour experience, restaurant, guy, local, room, jungle beach, morning, little hot, 
pagoda small, peaceful environment, view, ocean, car, eatables water, 
small garden, walk]

answered Mar 10, 2016 at 14:12

Mena

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2 Comments

MR AND Over a year ago

How would i approach this problem if I was using Java 1.6.

Mena Over a year ago

@AND uugh. Too lazy, sorry. Maybe someone else can tackle the pre-stream solution...

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