Arrays로 배열 다루기

배열 출력

1차원 배열 : Arrays.toString()

int[] arr = {0, 1, 2, 3, 4};
System.out.println(Arrays.toString(arr));
// [0, 1, 2, 3, 4]

2차원 배열 : Arrays.deepToString()

int[][] arr2D = {{11, 12}, {21, 22}};
System.out.println(Arrays.deepToString(arr2D));
// [[11, 12], [21, 22]]

 

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배열 비교

1차원 배열 : Arrays.equals()

2차원 배열 : Arrays.deepEquals()

String[][] str2D = {{"aaa", "bbb"}, {"AAA", "BBB"}};
String[][] str2D2 = {{"aaa", "bbb"}, {"AAA", "BBB"}};

System.out.println(Arrays.equals(str2D, str2D2)); // false
System.out.println(Arrays.deepEquals(str2D, str2D2)); // true

 

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배열 복사

Arrays.copyOf()

Arrays.copyOfRange(배열, from, to)

int[] arr = {0, 1, 2, 3, 4};
int[] arr2 = Arrays.copyOf(arr, arr.length); // arr2 = [0, 1, 2, 3, 4]
int[] arr3 = Arrays.copyOf(arr, 3); // arr3 = [0, 1, 2]
int[] arr4 = Arrays.copyOf(arr, 7); // arr4 = [0, 1, 2, 3, 4, 0, 0]
int[] arr5 = Arrays.copyOfRange(arr, 2, 4); // arr5 = [2, 3]
int[] arr6 = Arrays.copyOfRange(arr, 0, 7); // arr6 = [0, 1, 2, 3, 4, 0, 0]

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배열 정렬

오름차순 : Arrays.sort()

int[] arr = {3, 2, 0, 1, 4};
Arrays.sort(arr); // arr = [0, 1, 2, 3, 4]