无法从字符串中拆分数字值

Question

我正在为 java 中的区域转换程序创建一个 Udf 函数。我有以下数据：

230Sq.feet
110Sq.yards
8Acres
123Sq.Ft

我想把上面的数据拆分成这样：

230 Sq.feet
990 Sq.feet
344 Sq.feet
123 Sq.feet

我尝试了以下代码：

public class Areaconversion2 extends EvalFunc<String> {

public String determine_Area (String input) throws IOException
{
    String[] AreaArr = input.split("");
    Double Area;

    if(AreaArr[1].equalsIgnoreCase("Sq.Yards") || AreaArr[1].equalsIgnoreCase("Sq.Yds")) 
    {
    Area = Double.parseDouble(AreaArr[0]);
        Area = Area * 9;
        String Ar = Area.toString() + " Sq.Feet";
        return Ar;
    }
else if(AreaArr[1].equalsIgnoreCase("Acre") || AreaArr[1].equalsIgnoreCase("Acres")) 
{      
        Area = Double.parseDouble(AreaArr[0]);
        Area = Area * 43560;
        String Ar = Area.toString() + " Sq.Feet";
    return Ar;
 }
else if(AreaArr[1].equalsIgnoreCase("Sq.Feet)")||AreaArr[1].equalsIgnoreCase("Sq.Ft"));
      {
          Area = Double.parseDouble(AreaArr[0]); 
       String Ar = Area.toString() + " Sq.Feet";
          return Ar;
      }

    }

public String exec(Tuple input) throws IOException {
    // TODO Auto-generated method stub
     if (input == null || input.size() == 0)
         return null;

     try

     {

         String str = (String)input.get(0);

         return determine_Area(str);
         }catch(Exception e){
              throw new IOException("Caught exception processing input row ", e);
         }
}

}

我只在处理时遇到异常。任何帮助将不胜感激。

Answer 1

您可以使用 Pattern 和 Matcher.

而不是使用 split()

public static void main(String[] args) {
    String s = "230Sq.feet";
    Pattern p = Pattern.compile("(\d+)(\D+)"); // group 1 is the number part and group 2 is everything that follows the number part
    Matcher m = p.matcher(s);
    while (m.find()) {
        System.out.println(m.group(1));
        System.out.println(m.group(2));
    }
}
O/P :
230
Sq.feet

Answer 2

您可以使用look-ahead/look-behind匹配：

String[] fields = str.split("(?<=\d)(?=[A-Z])");

(?<=\d)是零长度匹配器，意思是"a digit must preceed"，(?=[A-Z])是零长度匹配器，意思是"a capital letter must be after matched string".

在您的数据上测试：

public static void main(String[] args) {
    String[] inputs = {"230Sq.feet", "110Sq.yards", "8Acres", "123Sq.Ft"};
    for(String input : inputs) {
        String[] fields = input.split("(?<=\d)(?=[A-Z])");
        System.out.println(fields[0]+" "+fields[1]);
    }
}

输出为：

230 Sq.feet
110 Sq.yards
8 Acres
123 Sq.Ft

无法从字符串中拆分数字值

not able to split the number value from the string

java

udf