Trying to find the sum of all numbers in an alphanumeric string having spaces(i.e. "my12 23name-CodePudding

I have tried with:

public class FindSumOfNumbersInString {

    public static void main(String[] args) {
        
        FindSumOfNumbersInString sum= new FindSumOfNumbersInString();
        
        sum.getNumerics("my12 23name 14 is bijay");
    }
    
    //"my12 23name 14 is bijay"
    
    public void getNumerics(String S) {
        String [] a= S.split(" ");
        int sum=0;
        for(int i=0;i<a.length;i  ) {
            String str=a[i].replaceAll("^0-9","");
             sum=sum Integer.parseInt(str);
            
        }System.out.println(sum);
        
    }

CodePudding user response：

It may be better to look for the strings matching integer numbers \d , then empty strings are not included in the match:

public static void getNumerics(String s) {
    Matcher m = Pattern.compile("\\d ").matcher(s);
    int sum = 0;
    while (m.find()) {
        sum  = Integer.parseInt(m.group(0));
    }
    System.out.println(sum);
}

Similar version using Stream API Matcher::results:

public static void getNumericsStream(String s) {
    int sum = Pattern.compile("\\d ").matcher(s)
            .results()
            .map(MatchResult::group)
            .mapToInt(Integer::parseInt)
            .sum();
    System.out.println(sum);
}

or Scanner::findAll:

public static void getNumericsScanner(String s) {
    int sum = new Scanner(s)
            .findAll("\\d ")
            .map(MatchResult::group)
            .mapToInt(Integer::parseInt)
            .sum();
    System.out.println(sum);
}

Also, the input string may be split by non-digit characters \D and the empty string(s) should be filtered out:

public static void getNumericsSplit(String s) {
    int sum = Arrays.stream(s.split("\\D "))
        .filter(x -> !x.isEmpty())
        .mapToInt(Integer::parseInt)
        .sum();
        
    System.out.println(sum);
}

All these methods print 49 for input "my12 23name 14 is bijay":

getNumerics("my12 23name 14 is bijay");       // 49
getNumericsStream("my12 23name 14 is bijay"); // 49
getNumericsScanner("my12 23name 14 is bijay");// 49
getNumericsSplit("my12 23name 14 is bijay");  // 49

CodePudding user response：

Instead of splitting the string inside the loop, you can split it outside the loop. I also recommend you replace [^0-9\s] with blank. The pattern, [^0-9\s] means non-digits or whitespace. Note the use of [ ] which is used to create character classes and after a pattern is used for one or more occurrences.

Demo:

public class Main {
    public static void main(String[] args) {
        System.out.println(getSumOfNumbers("my12 23name 14 is bijay"));
    }

    static int getSumOfNumbers(String str) {
        String[] a = str.replaceAll("[^0-9\\s]", "").split("\\s ");
        int sum = 0;
        for (int i = 0; i < a.length; i  )
            sum = sum   Integer.parseInt(a[i]);
        return sum;
    }
}

Output: