Get user to input only numbers or A-Z?

Question

static void a1()
{

   int choice;
   Scanner sc1 = new Scanner(System.in);
   System.out.println();
   System.out.print("Enter Part#: ");
   pa[count] = sc1.nextLine();

   System.out.println();
   System.out.print("Enter Make: ");
   ma[count] = sc1.nextLine();

   System.out.println();
   System.out.print("Enter description: ");
   so[count] = sc1.nextLine();

   System.out.println();
   System.out.print("Enter price: ");
   pr[count] = sc1.nextLine();

   ++count; 

 }

How do I get the user to input either only numbers or letters from A-Z?

You can adapt this answer to your needs. http://stackoverflow.com/a/13115310/2308683 — OneCricketeer, Jun 02 '16 at 12:54
`System.out.println("Please enter only numbers or letters from A-Z");` — vikingsteve, Jun 02 '16 at 13:03

duncan · Answer 1 · 2016-06-02T13:15:30.090

Wrap each section in a while loop. That repeats asking the user for input until they enter valid information.

do
{
    System.out.print("Enter Part#: ");
    pa[count] = sc1.nextLine();
}
while(checkAlpha(pa[count]) == false);

Then create a function to check each value in the string for valid characters.

public static boolean checkAlpha(String phrase)
{
    char[] tempChars = phrase.toCharArray();
    for(char c : tempChars)
    {
        if(!Character.isLetterOrDigit(c))
        {
            return false;
        }
    }
    return true;
}

You also could do this using regex by changing the while check to:

while(!pa[count].matches("^[a-zA-Z0-9]+$"));

Thank you for your reply and help :) I used regex and it worked! Thanks again :) — Firefox264, Jun 02 '16 at 14:11

score 0 · Answer 2 · edited Jun 02 '16 at 15:29

0

If you use the Pattern class to build a Matcher, you should be able to just use the pattern [^\\p{Alnum}] and then call the find() method to look for any matching instance of the pattern.

edited Jun 02 '16 at 15:29

ZGski

2,398
1
21
34

answered Jun 02 '16 at 14:15

Lee Painton

62
4

Get user to input only numbers or A-Z?

2 Answers2