Extract all integers from the given string in Java

Given a string str consisting of digits, alphabets and special characters. The task is to extract all the integers from the given string.

Examples:

Input: str = “geeksforgeeks A-118, Sector-136, Uttar Pradesh-201305”
Output: 118 136 201305

Input: str = ” 1abc35de 99fgh, dd11″
Output: 1 35 99 11

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

Replace all the non-digit characters with spaces (” “).
Now replace every consecutive group of spaces with a single space.
Eliminate the leading and the trailing spaces (if any) and the final string will only contain the required integers.

Below is the implementation of the above approach:

// Java implementation of the approach 
public class GFG { 
  
    // Function to return the modified string 
    static String extractInt(String str) 
    { 
        // Replacing every non-digit number 
        // with a space(" ") 
        str = str.replaceAll("[^\\d]", " "); 
  
        // Remove extra spaces from the beginning 
        // and the ending of the string 
        str = str.trim(); 
  
        // Replace all the consecutive white 
        // spaces with a single space 
        str = str.replaceAll(" +", " "); 
  
        if (str.equals("")) 
            return "-1"; 
  
        return str; 
    } 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        String str = "avbkjd1122klj4 543 af"; 
        System.out.print(extractInt(str)); 
    } 
} 

Output:

1122 4 543

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