Delete duplicate strings in string array

问题:

I am making a program based on string processing in Java in which I need to remove duplicate strings from a string array. In this program, the size of all strings are same.

The 'array' which is a string array contains a number of strings in which two strings resemble each other. So using the below code the duplicate string must get removed but it is not removed.

How to remove the duplicate strings?

I am using the following code.

    for(int s=0;s<array.length-1;s++)
    {
        for(int m=0;m<array.length;m++)
        {
                for(int n=0;n<array[m].length();n++)
                {   
                    if(array[s].charAt(n)==array[m].charAt(n))
                    {
                      continue;
                    }
                    else 
                break;
        } 
        if(n==array[m].length())
        {
            ArrayUtils.removeElement(array, array[s]);
        }
    }

回答1:

This will work

array = new HashSet<String>(Arrays.asList(array)).toArray(new String[0]);

or just use a HashSet instead of an array.

回答2:

Set<String> set = new HashSet<String>();
Collections.addAll(set, array);

or start with

for(int s=0;s<array.length-1;s++)
{
    for(int m=s + 1;m<array.length;m++)
    {

                if(array[s] != null && array[s].equals(array[m]))
                {
                  // array = ArrayUtils.removeElement(array, array[s]); --m;??
                  array[m] = null; // Mark for deletion later on
                }
    } 
}

回答3:

Unless this is [homework] I would use a Set

String[] array =
Set<String> uniqueWords = new HashSet<String>(Arrays.asList(array));

回答4:

import java.util.*;
public class Stringarray {

    public static void main(String args[]){

        String[] name = {"aim","rajesh","raju","aim"};

    Set<String> myset  = new HashSet<String>();
    Collections.addAll(myset,name);

       System.out.println(myset);
    }
}

回答5:

• Why don't you use String.equals() for comparison instead of iterating through the characters in the strings manually?
• Your logic is actually flawed: for array[s] == "12345" and array[m] == "123" it would claim that they are equal
• moreover, in your inner loop for(int m=0;m<array.length;m++) m will also become equal to s at some point, so you will compare a string to itself

These notes assume that you need to implement the removal logic with your own code, not being allowed to use the class library. If this is not the case, as others noted, using a HashSet is the simplest approach.

回答6:

Why didn't you remove the most inner loop with in favor of String.equals(String)?

In first iteration you are comparing array[0] with array[0] which are equal, and it would be removed. Then you will compare the original array[1] with all other elements in array, and if they are equal, you are removing array[1] (not the other one).

There are some problems, if there are some duplicate Strings, you are removing the first one, which will reduce the size of the array without reducing r so, some of the Strings in the array are skipped.

I would use a data structure which forces uniqueness, such as a Set.

What will happen if you have 3 equal Strings in your array, I'm not sure what will happen.

I believe you would encounter some ArrayIndexOutOfBoundsExceptions.

回答7:

I think the if condition at the end should be if(n==(array[m].length()-1))

Having said that, you seem to be trying to implement what String.equals() method does in your inner most loop.

回答8:

     String[] arr = {"w10","w20","w10","w30","w20","w40","w50","w50"};
     List<String> arrList = new ArrayList<String>();
     int cnt= 0;
       //List<String> arrList = Arrays.asList(arr);
       List<String> lenList = new ArrayList<String>();
          for(int i=0;i<arr.length;i++){
        for(int j=i+1;j<arr.length;j++){
           if(arr[i].equals(arr[j])){
             cnt+=1;
           }                
        }
        if(cnt<1){
          arrList.add(arr[i]);
        }
          cnt=0;
        }

for(int k=0;k<arrList.size();k++){
            System.out.println("Array without Duplicates: "+arrList.get(k));
        }

回答9:

Proposed solution does not keep the order of the elements. If you use Java 8 or higher and want to maintain the order you can use streams as follows:

array = Arrays.stream(array).distinct().toArray(String[]::new);

Full example: https://www.javacodeexamples.com/java-string-array-remove-duplicates-example/849

回答10:

Duplicate integer remove : this is the perfect answer /// Haris ///

public static void duplicateRemove(int[] arr) {
    int temp = 0;

    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr.length; j++) {
            if (arr[i] < arr[j]) {
                temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
    }

    int count;
    for (int j = 0; j < arr.length;) {
        count = 1;
        for (int i = j + 1; i < arr.length; i++) {
            if (arr[i] == arr[j]) {
                count++;
            } else
                break;

        }
        System.out.println(arr[j] + " is :  " + count);
        j += count;
    }

}