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java数组常用的方法总结
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1.? 声明一个数组
1 2 3 | String[] aArray = new String[5]; String[] bArray = {"a","b","c", "d", "e"}; String[] cArray = new String[]{"a","b","c","d","e"}; |
2. 输出一个数组
1 2 3 4 5 6 7 8 9 | 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] |
3. 从一个数组创建数组列表
1 2 3 4 | 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] |
4. 检查一个数组是否包含某个值
1 2 3 4 | String[] stringArray = { "a", "b", "c", "d", "e" }; boolean b = Arrays.asList(stringArray).contains("a"); System.out.println(b); // true |
5. 连接两个数组
1 2 3 4 | int[] intArray = { 1, 2, 3, 4, 5 }; int[] intArray2 = { 6, 7, 8, 9, 10 }; // Apache Commons Lang library int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2); |
6. 声明一个内联数组(Array inline)
1 | method(new String[]{"a", "b", "c", "d", "e"}); |
7. 把提供的数组元素放入一个字符串
1 2 3 4 5 | // 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 |
9. 将一个数组转换为集(set)
1 2 3 | Set<String> set = new HashSet<String>(Arrays.asList(stringArray)); System.out.println(set); //[d, e, b, c, a] |
10. 逆向一个数组
1 2 3 4 | int[] intArray = { 1, 2, 3, 4, 5 }; ArrayUtils.reverse(intArray); System.out.println(Arrays.toString(intArray)); //[5, 4, 3, 2, 1] |
11.移除数组中的元素
1 2 3 | int[] intArray = { 1, 2, 3, 4, 5 }; int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array System.out.println(Arrays.toString(removed)); |
12. 将整数转换为字节数组
1 2 3 4 5 | byte[] bytes = ByteBuffer.allocate(4).putInt(8).array(); for (byte t : bytes) { System.out.format("0x%x ", t); } |
java数组常用的方法总结