# 集合的理解和好处(Understanding and benefits of collections)-其他

## 集合的理解和好处(Understanding and benefits of collections)

### 集合的理解和好处

• 数组的不足之处：

长度开始时必须指定，而且一旦指定,不能更改
保存的必须为同一类型的元素
使用数组进行增加/删除元素的示意代码-比较麻烦

• 长度开始时必须指定，而且一旦指定,不能更改
• 保存的必须为同一类型的元素
• 使用数组进行增加/删除元素的示意代码-比较麻烦
• 写出Person数组扩容示意代码。
``````Person[] pers = new Person[1];//大小是1
per[0] = new Person();

//**增加新的Person对象？**
Person[] pers2 = new Person[pers.length+1];//创建新数组
for(){}//拷贝pers数组的元素到pers2
pers2[pers2.length-1] = new Person();//添加新的对象
``````
• 集合的好处：

可以动态保存任意多个对象,使用比较方便!
使用集合添加,删除新元素的示意代码-简洁了

• 可以动态保存任意多个对象,使用比较方便!
• 使用集合添加,删除新元素的示意代码-简洁了
————————

### Understanding and benefits of collections

The length must be specified at the beginning and cannot be changed once specified
Saved elements must be of the same type
Schematic code for adding / deleting elements using arrays – more troublesome
• The length must be specified at the beginning and cannot be changed once specified
• Saved elements must be of the same type
• Schematic code for adding / deleting elements using arrays – more troublesome
• Write the schematic code for expanding the capacity of the person array.
``````Person[] pers = new Person[1];//大小是1
per[0] = new Person();

//**增加新的Person对象？**
Person[] pers2 = new Person[pers.length+1];//创建新数组
for(){}//拷贝pers数组的元素到pers2
pers2[pers2.length-1] = new Person();//添加新的对象
``````
• Collection benefits:
You can dynamically save any number of objects, which is more convenient to use!
It provides a series of convenient methods to manipulate objects: add, remove, set, get, etc
Use the collection to add and delete the schematic code of new elements – concise
• You can dynamically save any number of objects, which is more convenient to use!
• It provides a series of convenient methods to manipulate objects: add, remove, set, get, etc
• Use the collection to add and delete the schematic code of new elements – concise