Java String length not working properly

Question

I isolated my original problem in this class. It is returning 2 2. The first time I executed this code I got 1 1, I'm going crazy, I don't understand this behavior

public class Test {

    public static void main(String[] args) {
        test("‎A");
    }


    public static void test(String cadena) {
        System.out.println(cadena.length());
        System.out.println("‎A".length());
    }

}

You have a non-printable character before the letter. See [HERE](https://i.stack.imgur.com/4ZjD8.png) — BackSlash, Jul 04 '18 at 14:34
This is not "returning" anything (which it should not, as the return type is `void`). — Scott Hunter, Jul 04 '18 at 14:35
Do this: `for (char c : cadena.toCharArray()) { System.out.printf("char: %d, %s%n", (int) c, c); }` — Hovercraft Full Of Eels, Jul 04 '18 at 14:35
Please do the test that I suggest. Your `"A"` has another invisible char in it. — Hovercraft Full Of Eels, Jul 04 '18 at 14:36
@Victor check the image. You have two characters. even if you see just one. That's what "non printable character" means: you don't see it, but it's there. The output is correct. — BackSlash, Jul 04 '18 at 14:37
You can have any number of non-printable characters in a String. e.g. `\u202e` is a zero-width character which causes all the characters after it to be printed backwords, even more "fun" is you can use it in variable names. — Peter Lawrey, Jul 04 '18 at 14:41

score 2 · Answer 1 · answered Jul 04 '18 at 14:38

2

Your "‎A" is actually a sequence of two code points, an unprintable one followed by a capital A letter.

"‎A".codePoints().forEach(System.out::println);

Will print:

8206
65

8206 is the Unicode Character 'LEFT-TO-RIGHT MARK' (U+200E) character.

answered Jul 04 '18 at 14:38

Karol Dowbecki

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Thank you all. Do you know how remove all characters but the letter. I have tried this without success : replaceAll("\\s", ""); – Víctor Jul 04 '18 at 14:46
If you need to cleanup input data use a whitelist approach, rather than excluding. It's safer. See [this answer](https://stackoverflow.com/a/49516025/1602555). – Karol Dowbecki Jul 04 '18 at 14:48

score 1 · Answer 2 · answered Jul 04 '18 at 14:40

1

You have invisible character in the A. Both are not the same

   System.out.println(cadena.hashCode());
   System.out.println("‎A".hashCode());
   System.out.println("‎A".equals(cadena));

Output:

65
254451
false

answered Jul 04 '18 at 14:40

Thiru

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Shanu Gupta · Answer 3 · 2018-07-04T14:43:29.633

0

This would always print:

1
1

in normal circumstances.

In your case you seem to have some garbage/non printable character before A in "A".

I suggest you to delete and re-write the phrase "A".

edited Jul 04 '18 at 14:43

answered Jul 04 '18 at 14:37

Shanu Gupta

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Gatusko · Answer 4 · 2018-07-04T16:06:18.243

Ok from previous answer there is an invisble characrter

"‎A".chars() .forEach(i -> System.out.println("there is a char:" + (char)i));

Will Print:

there is a char:‎
there is a char:A

I think someone wants to make a Joke to you with this invisible character.

--Edit--

In Java for removing A control character for your String you can use Regex:

public static void test(String cadena) {
    System.out.println(cadena.length());
   "‎A".chars() .forEach(i -> System.out.println("there is a char:" + (char)i));
   String b ="‎A".replaceAll("\\p{C}","");
   System.out.println(b.length());
    b.chars() .forEach(i -> System.out.println("there is a char:" + (char)i));
}

OutPut:

2
there is a char:‎
there is a char:A
1
there is a char:A

score 0 · Answer 5 · answered Jul 04 '18 at 14:48

0

I tried to compile your code online here since I don't have java in my pc, and I see that you have this character (left-to-right mark)

You can just remove the string and retype it. :)

answered Jul 04 '18 at 14:48

triForce420

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Java String length not working properly

5 Answers5