数组常用操作

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

posted on 2013-09-16 13:00  zjgtan  阅读(170)  评论(0编辑  收藏  举报

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