Question

How to count the frequency of the digits (0 to 9) in a string with Java

Answer 1

public class MyClass {
    private static void countDigits(String s) {
        int size = s.length();
        
    	if (size == 0) {
    		System.out.print("String is empry");
    		return;
    	}
    
    	int[] digit_frequency = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

    	for (int i = 0; i < size; i++) {
    		if (Character.isDigit(s.charAt(i)))	{
    			digit_frequency[s.charAt(i) - '0']++;
    		}
    	}
    
    	for (int j = 0; j < 10; j++) {
    		System.out.println(j + ": " + digit_frequency[j] + " times");
    	}
    }

    public static void main(String args[]) {
	    String s = "c23c++4523java23988rust82215";

	    countDigits(s);
    }
}






/*
run:

0: 0 times
1: 1 times
2: 5 times
3: 3 times
4: 1 times
5: 2 times
6: 0 times
7: 0 times
8: 3 times
9: 1 times

*/

 

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