# String-practice

**Repository Path**: fangdongy/String-practice

## Basic Information

- **Project Name**: String-practice
- **Description**: No description available
- **Primary Language**: Java
- **License**: Not specified
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2024-07-17
- **Last Updated**: 2024-07-18

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# String-practice
有一个不定长度的String，其中前面是字母，后边是数字,例如："abcd123.456", 要求写一个方法得到其中的数字以String的形式返回,数字保留小数点后两位， 不四舍五入，截去多余小数,例如："abcd123.456"，得到"123.45" 如果数字没有小数点,要得到两位为0的小数，例如："abcd123"，得到"123.00".

Java代码：
```
package com.example.test;

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

public class StringPractice {
    public static void main(String[] args) {
        System.out.println("numberString = " + getNumberString(null));
        System.out.println("numberString = " + getNumberString(""));
        System.out.println("numberString = " + getNumberString("abcd"));
        System.out.println("numberString = " + getNumberString("abcd123"));
        System.out.println("numberString = " + getNumberString("abcd123.4"));
        System.out.println("numberString = " + getNumberString("abcd123.45"));
        System.out.println("numberString = " + getNumberString("abcd123.456"));
    }

    private static String getNumberString(String str) {
        if(str==null) return "";
        String result = "";
        Pattern pattern = Pattern.compile("(\\d+(\\.\\d+)?)");
        Matcher matcher = pattern.matcher(str);
        if (matcher.find()) {
            result = matcher.group();
            if (result.contains(".")) {
                result += "00";
            } else {
                result += ".00";
            }
            result = result.substring(0, result.indexOf(".") + 3);
        }
        return result;
    }
}

```

```
输出结果：
numberString = 
numberString = 
numberString = 
numberString = 123.00
numberString = 123.40
numberString = 123.45
numberString = 123.45
```