Question

如何从数组或列表中删除两个连续的元素？

我有一个阵列：

new String[]{"FIRST", "SECOND", "SECOND", "THIRD", "FOURTH", "FIRST", "FOURTH"})

我应该从这个数组中删除两个连续的元素。

要删除的元素：＆＃34; FIRST＆＃34;，＆＃34; SECOND＆＃34;

删除元素后，新数组或列表应如下所示：

new String[]{"SECOND",  "FIRST", "FOURTH", "FIRST", "FOURTH"})

现在我已经：＆＃34; SECOND＆＃34;，＆＃34; FIRST＆＃34;

结果：new String[]{"FOURTH", "FIRST", "FOURTH"})

这是我的代码：

  String[] s1 = new String[arr.length];

    String n = "FIRST";
    String s = "SECOND";
    String w = "THIRD";
    String e = "FOURTH";


//I found two successive elements, and element next to them 
//My question is, how can I remove these element from list, 
or copy array without these elements to a new array?

   for (int i = 0; i <arr.length ; i++) {
        if (arr[i].equals(n) && arr[i + 1].equals(s)){
            System.out.println(arr[i + 2]);
        }
    }

如何从数组或列表中删除两个连续的元素？

Answer 1

public static void main(String[] args) {
        String[] arr = new String[]{"FIRST", "SECOND", "SECOND", "THIRD", "FOURTH", "FIRST", "FOURTH"};
        String[] toRemove = new String[]{"FIRST","SECOND"};
        arr=removeSuccessive(arr,toRemove);
        System.out.println(Arrays.toString(arr));
    }

    private static String[] removeSuccessive(String[] arr, String[] toRemove) {
        ArrayList<String> res=new ArrayList<>();
        for (int i = 0; i < arr.length; i++) {
            if(!arr[i].equals(toRemove[0]))
                    res.add(arr[i]);
            else if(i+1<arr.length && !arr[i+1].equals(toRemove[1]))
                    res.add(arr[i]);
            else
                i++;
        }

        return res.toArray(new String[res.size()]);
    }

您可以在此处检查并运行此代码： https://ideone.com/v6nPRf

Answer 2

您可以为此使用 regexp。将每个数组连接成一个带有一些分隔符 ⦀ 和 replace 的字符串:

String[] arr1 = {"FIRST", "SECOND", "SECOND", "THIRD", "FOURTH",
        "FIRST", "SECOND", "FIRST", "SECOND", "FIRST", "FOURTH"};

String[] arr2 = {"FIRST", "SECOND"};

// join each array into a single
// string with delimiter characters
String str1 = String.join("\u2980", arr1);
String str2 = String.join("\u2980", arr2);

String[] removed = Arrays
        .stream(str1
                // replace all occurrences of the second string
                // in the first string with delimiter characters
                .replaceAll(str2, "\u2980")
                // split a string around delimiter characters
                .split("\u2980"))
        // remove empty strings
        .filter(str -> str.length() > 0)
        .toArray(String[]::new);

System.out.println(Arrays.toString(removed));
// [SECOND, THIRD, FOURTH, FIRST, FOURTH]

Answer 3

package com.sash;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class SashStream {

    public static void main(String[] args) {
        String[] test = new String[] { "FIRST", "SECOND", "SECOND", "FIRST", "FOURTH", "FIRST", "FOURTH" };


        String[] out1 = filter(test, "FIRST", "SECOND");
        String[] out2 = filter(out1, "SECOND", "FIRST");

        System.out.println(Arrays.toString(out2));



    }

    private static String[] filter(String[] test, String first, String last) {
        List<String> outputList = new ArrayList<>();
        for (int i = 0; i < test.length; i++) {
            if((test.length-1)!=i && test[i].equals(first) && test[i+1].equals(last)){
                i++;
            } else {
                outputList.add(test[i]);
            }
        }
        return outputList.toArray(new String[0]);
    }

}

输出是：

[FOURTH, FIRST, FOURTH]

如何从数组或列表中删除两个元素的序列？

3 个答案: