Ten common methods of arrays tools

interpreter : Anchor

Translation date : 2013 year 11 month 19 Japan

Link to the original text : ​ ​Top 10 Methods for Java Arrays​​

The following is by  ​ ​stackoverflow Website ​​ Voted Java The ten most commonly used methods for arrays , 

0. Declaration 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"};
       
       

        
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1. Print array

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        int[] intArray = { 1, 2, 3, 4, 5 };
        
String intArrayString = Arrays.toString(intArray);
        

        
//  Print directly , Will print the reference object Hash value 
        
// [[email protected]
        
System.out.println(intArray);
        

        
// [1, 2, 3, 4, 5]
        
System.out.println(intArrayString);
       
       

        
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2. Create... From an array ArrayList

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        String[] stringArray = { "a", "b", "c", "d", "e" };
        
ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));
        
// [a, b, c, d, e]
        
System.out.println(arrayList);
       
       

        
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3. Check whether the array contains a value

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

        
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4. Merge and join 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);
       
       

        
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5. Declare inline arrays

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

        
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6. Link with the given string (join) Array

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

        
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7. take ArrayList Convert to 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);
       
       

        
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8. Convert an array to Set

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

        
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9. Array element inversion

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

        
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10. Remove elements

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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));
       
       

        
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more —— transformation int Values are byte arrays

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        byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
        

        
for (byte t : bytes) {
        
   System.out.format("0x%x ", t);
        
}
       
       

        
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