如何在java中拆分正负数字符串？

编程问答 2022-06-02

问题描述

输入：

String arrr[] = new String[4];

arrr[0] = +2501 +2502 +2503 +2504

arrr[1] = -2501 -2504 +2505 +2506 +2507 +2509

arrr[2] = +2501 +2511 -2502 -2505

arrr[3] = +2513 -2507 -2503 -2511 -2509

输出：

我想将字符串分隔为：

正面：

arrr1[0] = +2501 +2502 +2503 +2504

arrr1[1] = +2505 +2506 +2507 +2509

arrr1[2] = +2501 +2511

arrr1[3] = +2513

否定：

arrr2[0] = -2501 -2504

arrr2[1] = -2502 -2505

arrr2[2] = -2507 -2503 -2511 -2509

int nostrt = -1,m = 0;
StringBuilder str4 = new StringBuilder();
for(int i = 0;i < strbullist.length(); i++)
{    
    char c = strbullist.charat(i);

    if(nostrt == -1)
    {
        m = i;
        nostrt = 1; 
    }
    if(c=='-')
    {
        
        str4.append(strbullist.substring(m,i));
        nostrt = -1;
        System.out.println(str4);
    }    
}

解决方法

试试这个逻辑并根据您的需要进行更改。

导入 java.util.Scanner; 公开课 p19 {

 public static void main(String[] args) {
  Scanner sc=new Scanner(System.in);
  System.out.println("Enter the size of the array:");
     int size;
     size=sc.nextInt();
     int arr[ ]=new int[size];
  int i,j=0;
  System.out.println("Enter the Element of the array:");
      while(j<size)
     {
         arr[j]=sc.nextInt();
         j++;
     }
      System.out.println("Positive numbers are:");
      for(i=0;i<size;i++)
      {
          if(arr[i]>0)
          {
           System.out.print(arr[i]+" ");
          }
      }

      System.out.println("\nNegative numbers are:");
      for(i=0;i<size;i++){
          if(arr[i]<0)
          {
           System.out.print(arr[i]+" ");
          }
      }
     sc.close();
     }}
,

您可以将字符串拆分为一个或多个空白字符（即 \s+）并迭代结果数组以查找元素是以正号还是负号开头。

演示：

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        String str = "+2501 +2502 +2503 +2504 -2501 -2504 +2505 +2506 +2507 +2509 +2501 +2511 -2502 -2505 +2513 -2507 -2503 -2511 -2509";
        List<String> positiveNums = new ArrayList<>();
        List<String> negativeNums = new ArrayList<>();
        String[] arr = str.split("\\s+");

        for (String s : arr) {
            if (s.startsWith("+")) {
                positiveNums.add(s);
            } else if (s.startsWith("-")) {
                negativeNums.add(s);
            }
        }

        System.out.println("Positive numbers: " + positiveNums);
        System.out.println("Negative numbers: " + negativeNums);

        // If you want to store the output into string variables
        String positiveValues = positiveNums.toString();
        String negativeValues = negativeNums.toString();
        System.out.println("Positive numbers: " + positiveValues);
        System.out.println("Negative numbers: " + negativeValues);
    }
}

输出：

Positive numbers: [+2501,+2502,+2503,+2504,+2505,+2506,+2507,+2509,+2501,+2511,+2513]
Negative numbers: [-2501,-2504,-2502,-2505,-2507,-2503,-2511,-2509]
Positive numbers: [+2501,-2509]

或者，您也可以使用 regex、\+\d+|\-\d+ 表示 one or more 数字后跟加号（即 \+\d+）或（即 |）一位或多位数字后跟一个负号（即 \-\d+）。

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String str = "+2501 +2502 +2503 +2504 -2501 -2504 +2505 +2506 +2507 +2509 +2501 +2511 -2502 -2505 +2513 -2507 -2503 -2511 -2509";
        Matcher matcher = Pattern.compile("\\+\\d+|\\-\\d+").matcher(str);
        List<String> positiveNums = new ArrayList<>();
        List<String> negativeNums = new ArrayList<>();

        while (matcher.find()) {
            String s = matcher.group();
            if (s.startsWith("+")) {
                positiveNums.add(s);
            } else if (s.startsWith("-")) {
                negativeNums.add(s);
            }
        }

        System.out.println("Positive numbers: " + positiveNums);
        System.out.println("Negative numbers: " + negativeNums);
    }
}

输出：

Positive numbers: [+2501,-2509]

如果您想使用 StringBuilder 而不是 List：

public class Main {
    public static void main(String[] args) {
        String str = "+2501 +2502 +2503 +2504 -2501 -2504 +2505 +2506 +2507 +2509 +2501 +2511 -2502 -2505 +2513 -2507 -2503 -2511 -2509";
        StringBuilder positiveNums = new StringBuilder();
        StringBuilder negativeNums = new StringBuilder();
        String[] arr = str.split("\\s+");

        for (String s : arr) {
            if (s.startsWith("+")) {
                positiveNums.append(s + " ");
            } else if (s.startsWith("-")) {
                negativeNums.append(s + " ");
            }
        }

        String positiveValues = positiveNums.toString().trim();
        String negativeValues = negativeNums.toString().trim();
        System.out.println("Positive numbers: " + positiveValues);
        System.out.println("Negative numbers: " + negativeValues);
    }
}

输出：

Positive numbers: +2501 +2502 +2503 +2504 +2505 +2506 +2507 +2509 +2501 +2511 +2513
Negative numbers: -2501 -2504 -2502 -2505 -2507 -2503 -2511 -2509

使用 String#matches：

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        String str = "+2501 +2502 +2503 +2504 -2501 -2504 +2505 +2506 +2507 +2509 +2501 +2511 -2502 -2505 +2513 -2507 -2503 -2511 -2509";
        List<String> positiveNums = new ArrayList<>();
        List<String> negativeNums = new ArrayList<>();
        String[] arr = str.split("\\s+");

        for (String s : arr) {
            if (s.matches("\\+\\d+")) {
                positiveNums.add(s);
            } else if (s.matches("\\-\\d+")) {
                negativeNums.add(s);
            }
        }

        System.out.println("Positive numbers: " + positiveNums);
        System.out.println("Negative numbers: " + negativeNums);
    }
}

输出：

Positive numbers: [+2501,-2509]

更新（基于更新的问题）：

如果问题中的字符串是 String[] 的元素，则需要额外的循环来迭代此 String[]。其余的事情将保持不变。

public class Main {
    public static void main(String... args) {
        String[] strArr = { "+2501 +2502 +2503 +2504","-2501 -2504 +2505 +2506 +2507 +2509","+2501 +2511 -2502 -2505","+2513 -2507 -2503 -2511 -2509" };
        StringBuilder positiveNums = new StringBuilder();
        StringBuilder negativeNums = new StringBuilder();

        for (String str : strArr) {
            String[] arr = str.split("\\s+");
            for (String s : arr) {
                if (s.startsWith("+")) {
                    positiveNums.append(s + " ");
                } else if (s.startsWith("-")) {
                    negativeNums.append(s + " ");
                }
            }
        }

        String positiveValues = positiveNums.toString().trim();
        String negativeValues = negativeNums.toString().trim();
        System.out.println("Positive numbers: " + positiveValues);
        System.out.println("Negative numbers: " + negativeValues);
    }
}

输出：

Positive numbers: +2501 +2502 +2503 +2504 +2505 +2506 +2507 +2509 +2501 +2511 +2513
Negative numbers: -2501 -2504 -2502 -2505 -2507 -2503 -2511 -2509
,

如果你想把数字存储在一个字符串中，试试这个

        Scanner sc = new Scanner(System.in);
        System.out.print("Enter size : ");
        int size = sc.nextInt();
        
        String [] numbers = new String[size];
        String positive = "",negative = "";
        
        System.out.print("Enter number with signs (-) or (+) : ");
        for(int i = 0; i < size; i++){
            numbers[i] = sc.next();
        }
        
        for(int i =0; i < size; i++){
            if(numbers[i].contains("-")){
                negative += numbers[i] + " ";
            }else if(numbers[i].contains("+")){
                positive += numbers[i] + " ";
            }
        }
        
        System.out.println("Negatives : " + negative);
        System.out.println("Positives : " + positive);
javajavasplitsplitsplitstringstringstringbuilder