java常见数据结构举例

1. ArrayList(参考)

import java.util.*;
public class Test{
    public static void main(String [] args){
        ArrayList list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("c");
        System.out.println("size:" + list.size());
        System.out.println("contain:a?:" + list.contains("a"));
        System.out.println("contain:d?:" + list.contains("d"));
        }
}

输出

size:3
contain:a?:true
contain:d?:false

2. 数组

public class TestNew
{
     public static void main(String args[]) {
         int[] s ;
         int i ;
         s = new int[5] ;
         for(i = 0 ; i < 5 ; i++) {
             s[i] = i ;
         }
         for(i = 4 ; i >= 0 ; i--) {
             System.out.println("" + s[i]) ;
         }
     }
}

3. 字符串类型

trim(): 将String两端的空白字符删除

案例

import java.util.*;
public class SplitDemo
{
    public static void main(String[] args)
    {
        String input = "\t This!!\t";
        String input2 = input.trim();
        System.out.println(input + ":" + input.length());
        System.out.println(input2 + ":" + input2.length());
    }
}

结果

	 This!!	:9
This!!:6

split(): 以某个字符串切割

例子

import java.util.*;
public class SplitDemo
{
    public static void main(String[] args)
    {
        String input = "This!! umusual use!!of exclamation!!points";
        System.out.println(input);
        String arrayS1[] = input.split("!!");
        System.out.println(Arrays.toString(arrayS1));
        String arrayS2[] = input.split("!!", 3);
        System.out.println(Arrays.toString(arrayS2));
    }
}

结果

This!! umusual use!!of exclamation!!points
[This,  umusual use, of exclamation, points]
[This,  umusual use, of exclamation!!points]

说明

split()第二个参数表示分割的字符串个数不超过该参数