数组常用的API
首先import java.util.Arrays;
Arrays.asList()
将数组转换为列表
import java.util.Arrays;
import java.util.List;
public class stringAPi {
public static void main(String[] args) {
String[] strArray = {"huhuhu", "lilili", "foxfox"};
List<String> list = Arrays.asList(strArray);
// 将字符串打印
for(int i=0; i<list.size(); i++) {
System.out.print(list.get(i) + " ");
}
}
}
Arrays.copyOf()
import java.util.Arrays;
//复制长度大于原数组长度时,后面补零
public class copyOf {
public static void main(String[] args) {
int[] arr={1,3,5,7};
int[] copyOne= Arrays.copyOf(arr,3);
int[] copyTwo=Arrays.copyOf(arr,7);
//打印
for(int item:copyOne){
System.out.println(item + " ");
}
for(int item:copyTwo){
System.out.println(item + " ");
}
}
}
Arrays.binarySearch()
import java.util.Arrays;
//对数组进行二分查找
public class binarySearch {
public static void main(String[] args) {
int[] arr={1,4,3,6,77,234,52};
String[] arr2={"sS","ada","wwee"};
//二分查找之前保证数组的顺序
Arrays.sort(arr);
Arrays.sort(arr2);
int ind1=Arrays.binarySearch(arr,77);
int ind2=Arrays.binarySearch(arr,1);
int ind3=Arrays.binarySearch(arr2,"sS");
int ind4=Arrays.binarySearch(arr2,"wwee");
System.out.println("数字77的位置" + ind1);
System.out.println("数字1的位置" + ind2);
System.out.println("字符sS的位置" + ind3);
System.out.println("字符wwee的位置" + ind4);
}
}
Arrays.hashCode()
import java.util.Arrays;
public class hashCodeTest {
public static void main(String[] args) {
int[] a = {1,2,3,4,5,6};
int[] b = {1,2,3,4,5,6};
String[] c = {"a", "b", "c"};
String[] d = {"a", "b", "c"};
System.out.println("a==b:" + Arrays.equals(a, b));
System.out.println("a和b的哈希码分别为:" + Arrays.hashCode(a) + "\t" + Arrays.hashCode(b));
// 字符串
System.out.println("c==d:" + Arrays.equals(c, d));
System.out.println("c和d的哈希码分别为:" + Arrays.hashCode(c) + "\t" + Arrays.hashCode(d));
System.out.println("c==d:" + c.equals(d));
System.out.println("c和d的哈希码分别为:" + c.hashCode() + "\t" + d.hashCode());
}
}
Arrays.fill()
import java.util.Arrays;
public class fillTest {
public static void main(String[] args) {
int[] a = {1,2,3,4,5,6};
Arrays.fill(a, 8);//全部填充
for (int item : a)
System.out.print(item + " ");
System.out.println();
Arrays.fill(a, 1, 3, 0);//指定范围,替换
for (int item : a)
System.out.print(item + " ");
}
}