Java 从数组中删除重复项? [英] Java Remove Duplicates from an Array?

问题描述

我应该读入一个包含许多不同电子邮件地址的文件，并使用数组将它们打印出来.问题是我需要消除重复的电子邮件.

I am supposed to read in a file containing many different email addresses and print them out using an array. The problem is I need to eliminate duplicate emails.

我能够让我的 try/catch 工作并打印出电子邮件地址.但是，我不确定如何删除重复项.我还不了解哈希码或如何使用 Set.任何帮助将不胜感激.

I was able to get my try / catch working and print out the email addresses. However, I am not sure how to go about removing the duplicates. I do not have an understanding of hashcode's or how to use a Set yet. Any assistance would be appreciated.

这是我目前所拥有的:

import java.util.Scanner;
import java.io.*;

public class Duplicate {
   public static void main(String[] args) {

      Scanner keyboard = new Scanner(System.in);
      System.out.println("Enter file name: ");
      String fileName = keyboard.nextLine();
      if (fileName.equals("")) {
         System.out.println("Error: User did not specify a file name.");
      } else {
         Scanner inputStream = null;

         try {
            inputStream = new Scanner(new File(fileName));
         } catch (FileNotFoundException e) {
            System.out.println("Error: " + fileName + " does not exist.");
            System.exit(0);
         }

         String[] address = new String[100];

         int i = 0;
         while (inputStream.hasNextLine()) {
            String email = inputStream.nextLine();
            // System.out.println(email);

            address[i] = email;
            System.out.println(address[i]);
            i++;
         }
      }
   }
}

推荐答案

简单的解决方案是使用 Java 的 Set，

The Simple solution is that use Set of java,

所以设置自动删除重复值

so set remove duplicate value automatically

并且在您的代码中，您有数组而不是直接使用代码将数组转换为设置

and in your code you have array than convert array to set directly using code

Set<T> mySet = new HashSet<T>(Arrays.asList(someArray));

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