Question

我创建了一个程序，该程序从美国人口普查日期（link here）获取姓氏，并使用二进制搜索来查找用户的姓氏。要清楚，我对这部分代码有没问题。我遇到麻烦的地方是试图删除额外的信息。当我运行代码时，它返回整行。例如：

ROBINSON       0.233  8.372     20

当我想要的只是：

ROBINSON

如何解决此问题？我的代码如下：

import java.util.ArrayList;
import java.net.*;
import java.io.*;
import java.util.Scanner;
import java.util.Collections;
public class NameGuesser
{
public static void main(String[] args) throws IOException, MalformedURLException
{
    ArrayList<String> lastNames = new ArrayList<String>();
    URL url = new URL("http://www.census.gov/genealogy/www/data/1990surnames/dist.all.last");        
    Scanner in = new Scanner(url.openStream());
    while (in.hasNextLine())
    {
        lastNames.add(in.nextLine());
    }
    Collections.sort(lastNames);
    int low = 0;
    int high = lastNames.size();
    int loop = 0;
    int mid = 7;
    while(loop==0)
    {
        String t1 = lastNames.get(mid);
        mid = (low+high)/2;
        System.out.println("This program tries to guess your last name, but you have to give some hints.");
        System.out.println("Does your name come before " + lastNames.get(mid) + " in the dictionary? (Y/N)");
        Scanner input = new Scanner(System.in);
        String answer = input.nextLine();
        String t2 = lastNames.get(mid);
        if(t1.equals(t2))
        {
            System.out.println("Your name is " + t2);
            System.exit(0);
        }
        if(answer.equalsIgnoreCase("Y"))
        {
            high = mid;
        }
        if(answer.equalsIgnoreCase("N"))
        {
            low = mid;
        }

    }
}

}

Answer 1

这一点就在这里：

while (in.hasNextLine())
{
    lastNames.add(in.nextLine());
}

您正在阅读整行并将其添加到lastNames。数据以制表符分隔，所以为了摆脱额外的字段，你应该在之前将它放入lastNames：

while (in.hasNextLine()) { String lastNameLine = in.nextLine(); String [] parts = lastNameLine.split("\\t"); // Split by tabs. if(parts == null || parts.length < 0) { /* uh-oh... error condition */ } String lastName = parts[0]; lastNames.add(lastName); }

如何从URL OpenStream扫描中删除额外信息？

1 个答案: