循环删除List中的元素_list 循环删除

错误的示范

public static void main(String[] args) {
    List<String> platformList = new ArrayList<>();
    platformList.add("博客园");
    platformList.add("CSDN");
    platformList.add("掘金");
 
    for (String platform : platformList) {
        if (platform.equals("博客园")) {
            platformList.remove(platform);
        }
    }
 
    System.out.println(platformList);
}

主要原因就是，删除后，list对象发生变化，下标也变了。

正确的方式一：for循环，同时减少下标

public static void main(String[] args) {
    List<String> platformList = new ArrayList<>();
    platformList.add("博客园");
    platformList.add("CSDN");
    platformList.add("掘金");
 
    for (int i = 0; i < platformList.size(); i++) {
        String item = platformList.get(i);
 
        if (item.equals("博客园")) {
            platformList.remove(i);
            i = i - 1;
        }
    }
 
    System.out.println(platformList);
}

正确的方式二：Iterator对象的remove

public static void main(String[] args) {
    List<String> platformList = new ArrayList<>();
    platformList.add("博客园");
    platformList.add("CSDN");
    platformList.add("掘金");
 
    Iterator<String> iterator = platformList.iterator();
    while (iterator.hasNext()) {
        String platform = iterator.next();
        if (platform.equals("博客园")) {
            iterator.remove();
        }
    }
 
    System.out.println(platformList);
}

正确方式三：for循环，倒叙

public static void main(String[] args) {
    List<String> platformList = new ArrayList<>();
    platformList.add("博客园");
    platformList.add("CSDN");
    platformList.add("掘金");
 
    for (int i = platformList.size() - 1; i >= 0; i--) {
        String item = platformList.get(i);
 
        if (item.equals("掘金")) {
            platformList.remove(i);
        }
    }
 
    System.out.println(platformList);
}

正确方式四：stream filter过滤

public static void main(String[] args) {
 List<String> platformList = new ArrayList();
    platformList.add("博客园");
    platformList.add("CSDN");
    platformList.add("掘金");
    platformList = platformList.stream().filter(e -> !e.startsWith("博客园")).collect(Collectors.toList());
    System.out.println(platformList);
}