集合与数组的对比

package top.xxxx.www.CollectionDemo;import java.util.ArrayList;
import java.util.Arrays;public class CollectionDemo {public static void main(String[] args) {int[] arr = {1, 2, 3};String[] arr2 = {"a", "b", "c" };System.out.println(Arrays.toString(arr));System.out.println(Arrays.toString(arr2));ArrayList<Integer> arrl = new ArrayList<>();arrl.add(1);arrl.add(2);arrl.add(3);System.out.println(arrl);ArrayList<String> arrl2 = new ArrayList<>();arrl2.add("a");arrl2.add("b");arrl2.add("c");System.out.println(arrl2);}
}

集合体系结构

Collection——常见成员方法

package top.xxx.www.CollectionDemo;import javax.swing.*;
import java.util.ArrayList;
import java.util.Collection;public class CollectionDemo2 {public static void main(String[] args) {Collection<String> collection = new ArrayList<>();collection.add("aaa");collection.add("bbb");collection.add("ccc");System.out.println(collection);//删除方法boolean result = collection.remove("bbb");System.out.print(result + " ");System.out.println(collection);//条件删除方法boolean result2 = collection.removeIf((String s) -> {return s.equals("aaa");});System.out.print(result2 + " ");System.out.println(collection);//清空集合collection.clear();System.out.println(collection);//判断集合中是否存在指定的元素boolean result3 = collection.contains("ccc");System.out.println(result3);//判断集合是否为空boolean result4 = collection.isEmpty();System.out.println(result4);//集合的长度int size = collection.size();System.out.println(size);}
}

Collection——迭代器基本使用

Collection——迭代器原理分析

Collection——迭代器删除方法

增强for——基本格式

增强for——注意点

Collection——练习