List常见用法

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类型

ArrayList（长于随机访问元素，但是在中间插入和删除元素时较慢）
LinkList（优化了顺序访问，在随机访问方面相对较慢，特性集较ArrayList更大）

例子

    public static void print(String s){        System.out.println(s);    }//  Random rand = new Random(47);//  List<Pet> pets = Pets.arrayList(7);    public static void main(String args[]){        Random rand = new Random(47);        List<String> pets = new ArrayList();        pets.add("Rat");        pets.add("Manx");        pets.add("Cymric");        pets.add("Mutt");        pets.add("Pug");        pets.add("Cymric");        pets.add("Pug");        print("1: "+pets);        pets.add("Hamster");        print("2: "+pets);        print("3: "+pets.contains("Hamster"));        pets.remove("Hamster");        String p = pets.get(2);        print("4: "+p+" "+pets.indexOf(p) );        String cymric = "Cymric";        print("5: "+pets.indexOf(cymric));        print("6: "+pets.remove(cymric));        print("7: "+pets.remove(p));        print("8: "+pets);        pets.add(3,"Mouse");        print("9: "+pets);        List<String> sub = pets.subList(1, 4);        print("subList: "+sub);        print("10: "+pets.containsAll(sub));        Collections.sort(sub);        print("sorted subList: "+sub);        print("11: "+pets.containsAll(sub));        Collections.shuffle(sub,rand);        print("shuffle subList: "+sub);        print("12: "+pets.containsAll(sub));        List<String> copy = new ArrayList<String>(pets);        sub = Arrays.asList(pets.get(1),pets.get(4));        print("sub: "+sub);        copy.containsAll(sub);        print("13: "+copy);        copy = new ArrayList<String>(pets);        copy.remove(2);        print("14: "+copy);        copy.removeAll(sub);        print("15: "+copy);        copy.set(1, "Mouse");        print("16: "+copy);        copy.addAll(2,sub);        print("17: "+copy);        print("18: "+pets.isEmpty());        pets.clear();        print("19: "+pets);        print("20: "+pets.isEmpty());       }//output/* 5: 21: [Rat, Manx, Cymric, Mutt, Pug, Cymric, Pug]2: [Rat, Manx, Cymric, Mutt, Pug, Cymric, Pug, Hamster]3: true4: Cymric 25: 26: true7: true8: [Rat, Manx, Mutt, Pug, Pug]9: [Rat, Manx, Mutt, Mouse, Pug, Pug]subList: [Manx, Mutt, Mouse]10: truesorted subList: [Manx, Mouse, Mutt]11: trueshuffle subList: [Mouse, Manx, Mutt]12: truesub: [Mouse, Pug]13: [Rat, Mouse, Manx, Mutt, Pug, Pug]14: [Rat, Mouse, Mutt, Pug, Pug]15: [Rat, Mutt]16: [Rat, Mouse]17: [Rat, Mouse, Mouse, Pug]18: false19: []20: true     */

1.contains()方法来确定某个对象是否在列表内
2.remove()移除某个元素（若该元素有多个，移除所有该元素）
3.indexOf()获取对象在List中所处位置（获取第一个出现的位置）
4.subList(a,b)从列表中获得一个片段，左闭右开
5.containsAll()包含该集合的所有元素（Collecions.sort()和Collections.shuffle()（随机排序）不会影响）
6.retainAll()保留了同时在copy和sub中的元素（依赖于equals）
7.removeAll()移除所有元素
8.set(),replace()，替换
9.addAll()从制定位置插入一个列表
10.toArray()将Collection转换成一个数组

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