Common methods for arrays in Java

0. Create/Declare an array

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

　　

Print an array in 1.Java

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int[] intArray = { 1, 2, 3, 4, 5};String intArrayString = Arrays.toString(intArray); // print directly will print reference valueSystem.out.println(intArray);// [[email protected]System.out.println(intArrayString);// [1, 2, 3, 4, 5]

　

2. Create a ArrayList with an array

1234	String [ ] stringArray = { "a", "b" , "c" , "d" , "e" } ; ArrayList < String > arrayList = newArrayList < String > ( Arrays . asList ( stringArray ) ) ; System . out . println ( arrayList ) ; // [A，B，C，D，E]

　

3, check whether the array contains a specific value

123	String[] stringArray = { "a", "b", "c", "d", "e"};booleanb = Arrays.asList(stringArray).contains("a");System.out.println(b);

　　

4. Combining two arrays

1234	int[] intArray = { 1, 2, 3, 4, 5 };int[] intArray2 = { 6, 7, 8, 9, 10 };// Apache Commons Lang libraryint[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);

　　

5. Methods for declaring an array

1	method(newString[]{"a", "b", "c", "d", "e"});

　　

6, joins the elements in the supplied array into a string

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// containing the provided list of elements// Apache common langString j = StringUtils.join(newString[] { "a", "b", "c"}, ", ");System.out.println(j);// a, b, c

　

7. Conversion between array and list

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string[] Stringarray = { Code class= "Java plain", "C" "D" "E" arraylist<string> ArrayList = new arraylist<string> (arrays.aslist (Stringarray)); string[] Stringarr = new string[arraylist.size ()]; arraylist.toarray (Stringarr); for system.out.println (s);

　

8. Array conversion to set

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

　　

9. Array reverse output

1234	int[] intArray = { 1, 2, 3, 4, 5};ArrayUtils.reverse(intArray);System.out.println(Arrays.toString(intArray));//[5, 4, 3, 2, 1]

　　

10. Deleting an array element

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

　

Finally, int is converted into a byte array

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

Common methods for arrays in Java