• 直接拿来用!超实用的Java数组技巧攻略


    摘要:本文分享了关于Java数组最顶级的11大方法,帮助你解决工作流程问题,无论是运用在团队环境或是在私人项目中,你都可以直接拿来用。

    本文分享了关于Java数组最顶级的11大方法,帮助你解决工作流程问题,无论是运用在团队环境或是在私人项目中,你都可以直接拿来用! 

    0.  声明一个数组(Declare an array)

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    String[] aArray = new String[5];
    String[] bArray = {"a","b","c", "d", "e"};
    String[] cArray = new String[]{"a","b","c","d","e"};

    1.  在Java中输出一个数组(Print an array in Java)

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    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. 从数组中创建数组列表(Create an ArrayList from an array

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    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. 检查数组中是否包含特定值(Check if an array contains a certain value)

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    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( Concatenate two arrays)

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    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. 声明一个数组内链(Declare an array inline )

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    method(new String[]{"a", "b", "c", "d", "e"});

    6. 将数组元素加入到一个独立的字符串中(Joins the elements of the provided array into a single String)

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    // 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. 将数组列表转换成一个数组 (Covnert an ArrayList to an array)

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    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. 将数组转换成一个集合(Convert an array to a set)

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    Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
    System.out.println(set);
    //[d, e, b, c, a]

    9. 反向数组(Reverse an array)

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    int[] intArray = { 1, 2, 3, 4, 5 };
    ArrayUtils.reverse(intArray);
    System.out.println(Arrays.toString(intArray));
    //[5, 4, 3, 2, 1]

    10. 删除数组元素(Remove element of an array)

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    int[] intArray = { 1, 2, 3, 4, 5 };
    int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
    System.out.println(Arrays.toString(removed));

    One more – convert int to byte array

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    byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
      
    for (byte t : bytes) {
       System.out.format("0x%x ", t);
    }

    英文出自: Programcreek

    路漫漫其修远兮 吾将上下而求索
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  • 原文地址:https://www.cnblogs.com/hudabing/p/3323941.html
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