Extract digits from string - StringUtils Java

Question

I have a String and I want to extract the (only) sequence of digits in the string.

Example: helloThisIsA1234Sample. I want the 1234

It\'s a given that the s

Answer 1

I've created a JUnit Test class(as a additional knowledge/info) for the same issue. Hope you'll be finding this helpful.

   public class StringHelper {
    //Separate words from String which has gigits
        public String drawDigitsFromString(String strValue){
            String str = strValue.trim();
            String digits="";
            for (int i = 0; i < str.length(); i++) {
                char chrs = str.charAt(i);              
                if (Character.isDigit(chrs))
                    digits = digits+chrs;
            }
            return digits;
        }
    }

And JUnit Test case is:

 public class StringHelperTest {
    StringHelper helper;

        @Before
        public void before(){
            helper = new StringHelper();
        }

        @Test
    public void testDrawDigitsFromString(){
        assertEquals("187111", helper.drawDigitsFromString("TCS187TCS111"));
    }
 }

Answer 2

try this :

String s = "helloThisIsA1234Sample";
s = s.replaceAll("\\D+","");

This means: replace all occurrences of digital characters (0 -9) by an empty string !

Answer 3

You can also use java.util.Scanner:

new Scanner(str).useDelimiter("[^\\d]+").nextInt()

You can use next() instead of nextInt() to get the digits as string.

You can check for the presence of number using hasNextInt() on the Scanner.

Answer 4

Try this approach if you have symbols and you want just numbers:

    String s  = "@##9823l;Azad9927##$)(^738#";
    System.out.println(s=s.replaceAll("[^0-9]", ""));
    StringTokenizer tok = new StringTokenizer(s,"`~!@#$%^&*()-_+=\\.,><?");
    String s1 = "";
    while(tok.hasMoreTokens()){
        s1+= tok.nextToken();
    }
    System.out.println(s1);

Answer 5

You can use the following regular expression.

string.split(/ /)[0].replace(/[^\d]/g, '')

Answer 6

   `String s="as234dfd423";
for(int i=0;i<s.length();i++)
 {
    char c=s.charAt(i);``
    char d=s.charAt(i);
     if ('a' <= c && c <= 'z')
         System.out.println("String:-"+c);
     else  if ('0' <= d && d <= '9')
           System.out.println("number:-"+d);
    }

output:-

number:-4
number:-3
number:-4
String:-d
String:-f
String:-d
number:-2
number:-3