java - 您如何识别字符条目是否为两位数或更多位数字？

Question

我的意思是，如果我有一个由空格分隔的数组，我如何区分两个连续的字符是否是两个或更多数字？请耐心等待，总的来说，我对编程还是很陌生。

这是我目前所拥有的:

import java.util.*;
    public class calc 
    {
        public static String itemList;
        public static String str;
        public static void main(String[] args) 
        {
            Scanner sc = new Scanner(System.in);
            str = sc.nextLine();
            delimitThis();
            sc.close();
        }
        public static void delimitThis()// Delimiter to treat variable and                 numbers as seperate
        {
            List<String> items = Arrays.asList(str.split("\\s+"));
            System.out.println(items);

            for (int i = 0; i < str.length(); i++) 
             {
                    itemList = items.get(i);
                    category();

             }  
        }
        public static void category()////For Filtering between vars and constants and functions
        {
            for (int x = 0; x < itemList.length(); x++)
            {
               char ite = itemList.charAt(x);
        if(Character.isDigit(ite))
        {
            System.out.println(ite + "is numeric"); //Will be replaced by setting of value in a 2 dimensional list
            }
        }
    }

Answer 1

首先，我要纠正你的错误:

错误一:

// bad
for (int i = 0; i < str.length(); i++) 
{
    itemList = items.get(i);
    category();
}  

你正在遍历List<String> items ，但是str.length正在被使用。这是错误的。要{打印 item 然后执行 category() } 对于 items 中的每一项 ，代码应该是:

// fixed
for (int i = 0; i < items.size(); i++)
{
    itemList = items.get(i);
    category();
}

错误二:

for (int x = 0; x < itemList.length(); x++)
{
   System.out.println(itemList);
}

我不确定您想在这里做什么。只是你的代码对我来说没有意义。我假设你想打印 itemList 中的每个字符行，代码应如下所示:

for (int x = 0; x < itemList.length(); x++)
{
   System.out.println(itemList.charAt(x));
}

完成错误。现在检查一个字符串是否包含 2 位或更多数字，我们可以使用 String.matches()与 regular expression :

if(itemList.matches("\\d\\d+")){
    System.out.println(itemList + " is a two or more digit number");
}else{
    System.out.println(itemList + " is NOT a two or more digit number");
}

最后的代码是这样的:

import java.util.*;
public class Calc
{
    public static String itemList;
    public static String str;
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        str = sc.nextLine();
        delimitThis();
        sc.close();
    }
    public static void delimitThis()// Delimiter to treat variable and numbers as seperate
    {
        List<String> items = Arrays.asList(str.split("\\s+"));
        System.out.println(items);

        for (int i = 0; i < items.size(); i++)
        {
            itemList = items.get(i);
            category();
        }
    }
    public static void category()////For Filtering between vars and constants and functions
    {
        for (int x = 0; x < itemList.length(); x++)
        {
            System.out.println(itemList.charAt(x));
        }

        // is 2 digit number or not?
        if(itemList.matches("\\d\\d+")){
            System.out.println(itemList + " is a two or more digit number");
        }else{
            System.out.println(itemList + " is NOT a two or more digit number");
        }
    }
}