자바/Collections Framework
컬렉션프레임웍(Collections Framework) - Arrays 클래스
은은하게미친자
2022. 10. 1. 21:20
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package data_structure;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Stack;
class code1_ArraysClass {
public static void main(String[] args) {
System.out.println("array test");
int[] arr1= {1,2,30,5,4,7,8,10,2};
int[] arr2= {1,2,999,5,4,7,8,10,2};
Integer[] arr3 = new Integer[arr1.length];
int[][] arr4= {{1,2,3,4},{1,2,999,5,4,7,8,10,2}};
//tostring, deepToString
System.out.println(Arrays.toString(arr1));
System.out.println(Arrays.deepToString(arr4));
// 두배열 같은지 비교하기 다차원 배열은 deepEquals
System.out.println(Arrays.equals(arr1, arr2));
// 배열복사
arr2 = Arrays.copyOf(arr1, arr1.length);
System.out.println(Arrays.equals(arr1, arr2));
// 배열 원하는 만큼만 복사
arr2 = Arrays.copyOfRange(arr1, 5,arr1.length);
System.out.println(Arrays.toString(arr2));
// 배열정렬
Arrays.sort(arr2);
System.out.println(Arrays.toString(arr2));
// 리스트로 변환하기
List<Object> list = new ArrayList(Arrays.asList(arr2));
System.out.println("list " + list.toString());
// 배열 이진탐색 반반나눠서 탐색 , 이진탐색은 sort된 값에서 조회
System.out.println( Arrays.binarySearch(arr2,10) );
int i=0;
for (int a : arr1) {
arr3[i] = Integer.valueOf(a);
i++;
}
System.out.println("copy Integer: " +Arrays.toString(arr3));
// 배열정렬 내림차순
Arrays.sort(arr3, Collections.reverseOrder());
System.out.println(Arrays.toString(arr3));
// 배열값 특정값으로 초기화
Arrays.fill(arr2, 100);
System.out.println(Arrays.toString(arr2));
}
}
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