remove element frome array of string

Question

I made a function to delete a specific element in the array, but the problem that am struggling with is that when we getting the value of the element that we want to remove from s.next() it's not removing but when we already initialized a value for it it is removing

for example, we have a function remove

 public static String[] remove(String[] element, String value) {

        int validSize = 0;
        String[] n_elements = new String[0];
        for (int i = 0; i < element.length; i++) {
            if (element[i] == value) {
                element[validSize] = element[i];
                validSize++;
            }

            n_elements = new String[validSize];
            if (validSize >= 0) System.arraycopy(element, 0, n_elements, 0, validSize);


        }

        return n_elements;
    }

in main

public static void main(String[] args) {

 
    String[] group_A = {"Alexandr", "Ahmed", "Maria", "elf", "Omar", "Mariam"};

    Scanner s  = new Scanner(System.in);     

    System.out.println(Arrays.toString(group_A));

    String value = "elf";

//we already initialized a value for it

    group_A = remove(group_A,value);
    System.out.println(Arrays.toString(group_A));
}

}

output is correct

[Alexandr, Ahmed, Maria, elf, Omar, Mariam]
[Alexandr, Ahmed, Maria, Omar, Mariam]

but if we get value from the user in put it does not deleting

 String value = s.next();

output is

[Alexandr, Ahmed, Maria, elf, Omar, Mariam]
elf
[Alexandr, Ahmed, Maria, elf, Omar, Mariam]

Try to compare String using .equals() method, the "==" compare the references not the content of the Strings . element[i] == value ===> element[i].equals(value) — Oussama ZAGHDOUD, Oct 15 '21 at 09:12
Does this answer your question? [How do I compare strings in Java?](https://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — maloomeister, Oct 15 '21 at 09:31
in any place , when you like to compare the content of two Strings , use the method ".equals()" , the "==" is used to comapre if two strings are exactly the same object in the memory . in your case you have two string that have the same content but every one is an independent object in the memory , you need to read about hw to compare String in java and try to read about String Pool in java to more understand .thanks — Oussama ZAGHDOUD, Oct 15 '21 at 09:32

score 0 · Answer 1 · answered Oct 15 '21 at 09:26

0

Like @Oussama ZAGHDOUD said,

Instead of if (element[i] == value) , Use if (element[i].equals(value)).

answered Oct 15 '21 at 09:26

Arsh Coder

688
9
33

in this case, its only print the specific element that we want to delete – GBR Oct 15 '21 at 09:42
[Alexandr, Ahmed, Maria, elf, Omar, Mariam] input >> elf output >>[elf] – GBR Oct 15 '21 at 09:42

score 0 · Answer 2 · answered Oct 15 '21 at 09:51

Your code miss a "!" before the condition and you need to use .equals() instead of"==":

public static String[] remove(String[] element, String value) {

        int validSize = 0;
        String[] n_elements = new String[0];
        for (int i = 0; i < element.length; i++) {
            if (! element[i] .equals( value )) {
                element[validSize] = element[i];
                validSize++;
            }
            n_elements = new String[validSize];
            if (validSize >= 0) System.arraycopy(element, 0, n_elements, 0, validSize);
        }
        return n_elements;
    }

public static void main(String[] args) throws IOException {
     String[] group_A = {"Alexandr", "Ahmed", "Maria", "elf", "Omar", "Mariam"};
        Scanner s  = new Scanner(System.in);     
        System.out.println(Arrays.toString(group_A));
        String value = s.nextLine();
        //we already initialized a value for it
        group_A = remove(group_A,value);
        System.out.println(Arrays.toString(group_A));
}

remove element frome array of string

2 Answers2