how to check String start or end with space

Question

Enter the player name. The name must be between 1 and 6 characters in length and not begin or end with a space character. If not meet the requirement reenter the name.

import java.util.Scanner;

public class Player
{

    public void acceptName()
    {
        System.out.println("Please enter playrname");
        Scanner scanner = new Scanner(System.in);
        String playerName = scanner.nextLine();
        while(playerName.length() < 1 || playerName.length() > 6)
        {
            System.out.println("Name length over 6,Please re-enter playername");
            playerName = scanner.nextLine();
        }            
    }        
}

Possible duplicate of [Java - Trim leading or trailing characters from a string?](https://stackoverflow.com/questions/25691415/java-trim-leading-or-trailing-characters-from-a-string) — Sander Toonen, Apr 05 '19 at 06:58

Arnaud · Answer 1 · 2019-04-05T06:57:25.137

3

String.trim() will remove leading and trailing spaces, so comparing the length of the original string with the length of the trimmed one, should do the trick :

boolean hasLeadingOrTrailingSpaces = playerName.trim().length() != playerName.length();

edited Apr 05 '19 at 06:57

answered Apr 05 '19 at 06:52

Arnaud

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It is not correct, cause name could be like "Xi yan" – Dred Apr 05 '19 at 06:54
@Dred : The question was about a string starting or ending with spaces, not containing spaces. – Arnaud Apr 05 '19 at 06:55

score 3 · Answer 2 · answered Apr 05 '19 at 06:55

3

You can check it with Character.isWhitespace() function:

if (Character.isWhitespace(playerName.charAt(0)) 
  || Character.isWhitespace(playerName.charAt(playerName.length() - 1)) {
   //do your stuff
}

answered Apr 05 '19 at 06:55

Pavel Smirnov

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score 1 · Answer 3 · answered Apr 05 '19 at 06:56

1

You can use something like

if(playerName.startsWith(" ")||playerName.endsWith(" ")){
        System.out.println("Incorrect name;
}

answered Apr 05 '19 at 06:56

Dred

1,076
8
24

score 0 · Answer 4 · edited Apr 05 '19 at 07:35

0

Find length of entered string
Perform (String.trim()).length()
Compare length ..

edited Apr 05 '19 at 07:35

Pavel Smirnov

4,611
3
18
28

answered Apr 05 '19 at 07:01

HS447

81
9

how to check String start or end with space

4 Answers4