java基础-数组(二)
编程语言
2018-05-12 09:46:07
阅读次数: 2
原文地址:http://www.longluo.me/blog/2016/08/06/Top-10-Methods-For-Java-Arrays/
0. 声明一个数组
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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. 打印数组
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int[] intArray = { 1, 2, 3, 4, 5 };
String intArrayString = Arrays.toString(intArray);
System.out.println(intArray);
System.out.println(intArrayString);
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2. 从一个数组中创建一个ArrayList
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String[] stringArray = { "a", "b", "c", "d", "e" };
ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));
System.out.println(arrayList);
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3. 判断数组中是否包含一个特定的值
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String[] stringArray = { "a", "b", "c", "d", "e" };
boolean b = Arrays.asList(stringArray).contains("a");
System.out.println(b);
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4. 连接2个数组
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int[] intArray = { 1, 2, 3, 4, 5 };
int[] intArray2 = { 6, 7, 8, 9, 10 };
int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2); |
5. 声明一个inline数组
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method(new String[]{"a", "b", "c", "d", "e"}); |
6. 将一个数组中元素变成一个字符串
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String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");
System.out.println(j);
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7. 将一个ArrayList转换成一个数组
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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. 将一个数组转换成一个Set
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Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
System.out.println(set);
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9. 反转一个数组
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int[] intArray = { 1, 2, 3, 4, 5 };
ArrayUtils.reverse(intArray);
System.out.println(Arrays.toString(intArray));
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10. 从一个数组中删除一个单元
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int[] intArray = { 1, 2, 3, 4, 5 };
int[] removed = ArrayUtils.removeElement(intArray, 3);
System.out.println(Arrays.toString(removed)); |
One more - 将int转换成一个byte array
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byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
for (byte t : bytes) {
System.out.format("0x%x ", t);
} |
以上!
转载自lgclove1314.iteye.com/blog/2324091