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  • Java数组的十大方法

    Java数组的十大方法
    以下是Java Array的前10种方法。他们是来自stackoverflow的投票最多的问题。

    • 0.声明一个数组
    String[] aArray = new String[5];
    String[] bArray = {"a","b","c", "d", "e"};
    String[] cArray = new String[]{"a","b","c","d","e"};
    
    • 1.用Java打印数组
    int[] intArray = { 1, 2, 3, 4, 5 };
    String intArrayString = Arrays.toString(intArray);
    // print directly will print reference value
    System.out.println(intArray);
    // [I@7150bd4d
    System.out.println(intArrayString);
    // [1, 2, 3, 4, 5]
    
    • 2.从数组中创建一个ArrayList
    String[] stringArray = { "a", "b", "c", "d", "e" };
    ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));
    System.out.println(arrayList);
    // [a, b, c, d, e]
    
    • 3.检查数组是否包含某个值
    String[] stringArray = { "a", "b", "c", "d", "e" };
    boolean b = Arrays.asList(stringArray).contains("a");
    System.out.println(b);
    // true
    
    • 4.连接两个数组
    int[] intArray = { 1, 2, 3, 4, 5 };
    int[] intArray2 = { 6, 7, 8, 9, 10 };
    // Apache Commons Lang library
    int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);
    
    • 5.内联声明一个数组
    method(new String[]{"a", "b", "c", "d", "e"});
    
    • 6.将提供的数组的元素连接成单个字符串
    // containing the provided list of elements
    // Apache common lang
    String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");
    System.out.println(j);
    // a, b, c
    
    • 7.将ArrayList包含到数组中
    String[] stringArray = { "a", "b", "c", "d", "e" };
    ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));
    String[] stringArr = new String[arrayList.size()];
    arrayList.toArray(stringArr);
    for (String s : stringArr)
    	System.out.println(s);
    
    • 8.将数组转换为集合
    Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
    System.out.println(set);
    //[d, e, b, c, a]
    
    • 9.反转一个数组
    int[] intArray = { 1, 2, 3, 4, 5 };
    ArrayUtils.reverse(intArray);
    System.out.println(Arrays.toString(intArray));
    //[5, 4, 3, 2, 1]
    
    • 10.删除数组的元素
    int[] intArray = { 1, 2, 3, 4, 5 };
    int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
    System.out.println(Arrays.toString(removed));
    
    • 再多一个 - 将int转换为字节数组
    byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
    for (byte t : bytes) {
       System.out.format("0x%x ", t);
    }
    

    转:https://www.programcreek.com/2013/09/top-10-methods-for-java-arrays/

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  • 原文地址:https://www.cnblogs.com/hgnulb/p/9001876.html
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