Question

How to check if a given string is a valid float in Java

Answer 1

public class MyClass {
    public static void main(String args[]) {
        String s1 = "3.14"; 
        String s2 = "2182"; 
        String s3 = "8.92F";
        String s4 = "D7.13"; 
          
        try 
        { 
            Float.parseFloat(s1); 
            System.out.println(s1 + " is a valid float"); 
        }  
        catch (NumberFormatException e)  
        { 
            System.out.println(s1 + " is not a valid float"); 
            System.out.println(e);
        } 
          
        try 
        { 
            Float.parseFloat(s2); 
            System.out.println(s2 + " is a valid float"); 
        }  
        catch (NumberFormatException e) 
        { 
            System.out.println(s2 + " is not a valid float");
            System.out.println(e);
        } 
        
        try 
        { 
            Float.parseFloat(s3); 
            System.out.println(s3 + " is a valid float"); 
        }  
        catch (NumberFormatException e) 
        { 
            System.out.println(s3 + " is not a valid float");
            System.out.println(e);
        }
        
        try 
        { 
            Float.parseFloat(s4); 
            System.out.println(s4 + " is a valid float"); 
        }  
        catch (NumberFormatException e) 
        { 
            System.out.println(s4 + " is not a valid float");
            System.out.println(e);
        }
    }
}



/*
run:

3.14 is a valid float
2182 is a valid float
8.92F is a valid float
D7.13 is not a valid float
java.lang.NumberFormatException: For input string: "D7.13"

*/

 

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