CODEWITHSUNDEEP
java
maram05
maram05

Reputation: 59

Comparing the elements of an arrayList with one another

I have an array list with four object elements in it and i need to compare these objects with each other. I need to avoid the similar object comparisons and doing a continue in case if both objects are same. I have tried the below code but it's avoiding the common object iterations. Can anyone suggest me a best way to compare the elements in the same Array list?

Code:

List<Student> studentInfo= new ArrayList<Student>();

 for (int i = 0; i < list.size(); i++)
            {
                for (int j = 0 ; j < list.size(); j++)
                {


                    if(list.get(i).getstudentId().equals(list.get(j).getstudentId())) 
                    continue;

                    }

                }

            }

Upvotes: 0

Views: 2868

Answers (2)

Walter
Walter

Reputation: 279

You can use the bubble sort algorithm but instead of sort, you could use it for your needs.

A more elegant method to compare would be:

public class Student {

    private String id;

    /**
     * @return the id
     */
    public String getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public void setId(String id) {
        this.id = id;
    }



    @Override
    public boolean equals (Object otherObject){
        if(!(otherObject instanceof Student)){
            return false;
        }
        if(((Student)otherObject).getId().equals(this.id)){
            return true;
        }
        return false;
    }

}

In your class:

for(int i = 0; i< studentList.size(); i++){
    for(int j = i+1; j< studentList.size(); j++){
        if(studentList.get(i).equals(studentList.get(j))){
            continue;
        }
    }
}

Upvotes: 0

Sharon Ben Asher
Sharon Ben Asher

Reputation: 14383

you need to avoid the case where i == j in which case your if will evaluate to true 

if(i != j && list.get(i).getstudentId().equals(list.get(j).getstudentId())) 
  break;

if you want to know at the exit of the loop if you found a duplicate, you need an external variable to let you know (like boolean or perhaps an int that will show where the duplicate was found)

Upvotes: 3

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