how to check if a user's input follows the correct format

I want to write a program to ask the user's age, gender, name. Are there any simpler methods which I can use to check if the input is following the correct format?

The correct format is: name -- age -- gender

For example, Bob -- 22 -- M

public static void main (String[] args){
      
       Scanner scan = null;
       String info = null;

       while (true){

            scanner = new Scanner (System.in);
            info = scanner.nextLine();
            if (!info.contains("--") || !info.contains(" ")){
                   System.err.println("invalid format");
                   continue;
             }
            
             String infoList = info.split("--");

             
             // I need to check if the input contains any other sign such as ~,! and if there are 
             // exactly 3 inputs
             // so the list should be {X,Y,Z}, I also need to check if the age is a number rather 
             //than a letter or a sign.
            
}

If I write my program like that (use if condition to check every possible invalid condition), which will make my program long-winded.

Best way to do it would be using regular expressions rather than splitting the string into and array and checking each item indidually.

This regex should work:

[A-Za-z]+ -- [0-9]{1,2} -- [MF]

You can then check if any string matches this expression

String regex = "[A-Za-z]+ -- [0-9]{1,2} -- [MF]";
String testString = "Bob -- 22 -- M";

if(testString.matches(regex)) {
    // testString matches the regex
} else {
    // testString doesnt match the regex
}

After checking that the expression matches you could split the string and be able to manipualte each of the elements individually. Remeber to split by " -- " rather than "--" else you will get spaces in the string which can give problems later when manipulating the data.

If you want to understand better how regex works I would recommend you to search a bit about it as it can be very useful.

You can use Regex

String info = "Bob--22--M";

if (info.matches("[a-zA-z]+--[0-9]{2}--[MFmf]")){
    System.out.println("invalid format");
}

See regex here

You can do a simple method for each verification and then only call that method.

String[] infoList = info.split("--");
// infoList[0]should be the name, infoList[1] should be the age and infoList[2] should be the gender

if(!checkFormat(infoList[1],infoList[2])){
   System.out.println("invalid format");
   return;
}

method for verification:

private boolean checkFormat(String age, String gender){

  try
  {
      int aux =Integer.parseInt("age");  
  }
  catch(Exception)
  {
      return false;
  }
  if(!(gender.Equals("M") || gender.Equals("F")))
  {
      return false;
  }
  return true;
}

About the name, unless you have some especification, I can't do nothing about it.