比较字符串数组的数组列表 [英] Comparing array list of string array

问题描述

我想比较两个字符串数组的ArrayList.

I want to compare two ArrayList of string arrays.

   List<String[]> list1 = new ArrayList<String[]>;
   List<String[]> list2 = new ArrayList<String[]>;

   list1.equals(list2);

这将返回false，因为ArrayList中的equals方法将对元素执行equals.

This will return false because equals method in ArrayList will do equals on the element.

    ListIterator<E> e1 = listIterator();
    ListIterator<?> e2 = ((List<?>) o).listIterator();
    while (e1.hasNext() && e2.hasNext()) {
        E o1 = e1.next();
        Object o2 = e2.next();
        if (!(o1==null ? o2==null : o1.equals(o2)))
            return false;
    }
    return !(e1.hasNext() || e2.hasNext());     

如果对数组执行相等操作，它将检查引用是否相等.无论如何，我们可以使用list1.equals(list2)代替检查数组列表中的每个元素.

If you do equals on array, it will check reference equality. Is there anyway we can use list1.equals(list2) instead of checking each element in array list.

推荐答案

如果从 List< String []> 更改为 List<列表< String>> .

public static void main(String[] args) throws Exception {
    List<List<String>> list1 = new ArrayList() {{
       add(new ArrayList(Arrays.asList("a", "b", "c"))); 
       add(new ArrayList(Arrays.asList("d", "e", "f")));
       add(new ArrayList(Arrays.asList("g", "h", "i")));
    }};
    List<List<String>> list2 = new ArrayList()  {{
       add(new ArrayList(Arrays.asList("a", "b", "c"))); 
       add(new ArrayList(Arrays.asList("d", "e", "f")));
       add(new ArrayList(Arrays.asList("g", "h", "i")));
    }};

    System.out.println(list1);
    System.out.println(list2);
    System.out.println(list1.equals(list2));
}

结果:

[[a, b, c], [d, e, f], [g, h, i]]
[[a, b, c], [d, e, f], [g, h, i]]
true

否则，您可能正在按照以下方式寻找东西:

Otherwise, you're probably looking something along the lines of:

public static void main(String[] args) throws Exception {
    List<String[]> list1 = new ArrayList() {{
       add(new String[] {"a", "b", "c"}); 
       add(new String[] {"d", "e", "f"});
       add(new String[] {"g", "h", "i"});
    }};
    List<String[]> list2 = new ArrayList()  {{
       add(new String[] {"a", "b", "c"}); 
       add(new String[] {"d", "e", "f"});
       add(new String[] {"g", "h", "i"});
    }};

    System.out.println(listsEqual(list1, list2));
}

public static boolean listsEqual(List<String[]> list1, List<String[]> list2) {
    if (list1.size() != list2.size()) {
        return false;
    }

    for (int i = 0; i < list1.size(); i++) {
        if (!Arrays.equals(list1.get(i), list2.get(i))){
            return false;
        }
    }
    return true;
}

结果:

true

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