Question

我正在使用arraylists来查找两个字符串之间的差异，即str2和str3。当我使用下面的代码时，它完美地工作并返回预期的输出。但当我更换

str2 = #19, 6th cross, 7th main road, townname, cityname-560036
str3 = #19, 6th cross, 17th main road, townname, cityname-560036

预期输出应为：al1的内容：[1]

但我获得的输出是：al1的内容：[]

有谁可以解释我哪里出错？

提前致谢。

这是我的doPost方法：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
            str2="Hello";
    str3="Hallo";
    System.out.println("-------");
    System.out.println("This is first string:"+""+str2);
    System.out.println("This is second string:"+""+str3);


    ArrayList al = new ArrayList();
    ArrayList al1=new ArrayList(); 

      System.out.println("Initial size of al: " + al.size());

      // add elements to the array list
      for (int i = 0;i < str2.length(); i++)
        {
            al.add(str2.charAt(i));
        }
      System.out.println("Size of al after additions: " + al.size());

      // display the array list
      System.out.println("Contents of al: " + al);



      for (int i = 0;i < str3.length(); i++)
        {
            al1.add(str3.charAt(i));
        }

      System.out.println("Contents of al1: " + al1);

      System.out.println("Size of al1 after additions: " + al1.size());
        boolean hg=al1.removeAll(al);
        System.out.println("Remove All:"+hg);


      System.out.println("Contents of al: " + al);
      System.out.println("Contents of al1: " + al1);

}

Answer 1

你已经将“1”字符设置为“＃19”所以当你调用全部删除时，所有'1'都会被移除，包括你期望保留的那个。我认为你应该遍历字符并提取差异，否则比较将不会非常准确。

Answer 2

要解决您的问题，请使用String .split()方法

str2 = #19, 6th cross, 7th main road, townname, cityname-560036
str3 = #19, 6th cross, 17th main road, townname, cityname-560036

String[] s2 = str2.split(",");
String[] s3 = str3.split(",");

for (int i = 0; i < s2.length; i++) {
    al.add(s2[i]);
}

for (int i = 0; i < s3.length; i++) {
    al1.add(s2[i]);
}

al.retainAll(al1);

System.out.println("Size of a1 is " + a1.size());

此外，我认为你想要retainAll()而不是removeAll()。 retainAll()是返回boolean而不是removeAll()

的{{1}}

Answer 3

从我看到的地方：看起来你需要比较用逗号分隔的标记。创建strs的字符串列表（由'，'拆分），然后你可以删除类似的字符串，剩余的可以比较差异。

list.removeAll（）的问题

3 个答案: