Static array and loop in java

Question

I have a static array which is: String[] tab = {"Eva", "Ali", "David", "Maxime"};

If the name is bigger that 4 characters I have to put the items in another array. I know how to do this with an arraylist, but I want to try with a static array.

Here is an idea of my code but I am stuck in my loop.

class Main {

    public static void main(String[] args) {
        String[] tab = {"Eva", "Ali", "David", "Maxime"};

        for (String elt : tab) {
            if (elt.length() > 4) {
                // ????
            }
        }
    }
}

Thank you for your help.

it's unclear what you want to do. Plus, in your example the method is static but the array is a local variable. That doesn't make it a static array. — jhamon
– jhamon, Commented Nov 20, 2019 at 10:43
Well, what do you want to do with the array in that case ? 1) You can set the corresponding value to null OR 2) You can rebuild the array OR 3) You could keep valid values in a List and rebuild the "valid" array at the end. It is up to you — Arnaud Denoyelle
– Arnaud Denoyelle, Commented Nov 20, 2019 at 10:46
@jhamon by "a static array" OP meant "a constant-sized array" which is simply "an array" in Java. To answer this question is to show the contrast between List#add and anotherArray[i++] and to replace the for-each with a plain for — Andrew
– Andrew, Commented Nov 20, 2019 at 10:47
You could do two passes: the first one to count how many strings are longer than 4 characters, and the second one to populate the appropriately sized array. — DodgyCodeException
– DodgyCodeException, Commented Nov 20, 2019 at 10:47

Youcef LAIDANI · Accepted Answer · 2019-11-20 10:45:33Z

2

It's not possible to create an open size array, you have to define the number of element that can be in the array, But If you are using Java8 you can use stream like so :

String[] result = Arrays.stream(tab)
        .filter(elt -> elt.length() > 4)
        .toArray(String[]::new);

like this you don't need to define the result array before you fill it, you don't even need the size.

answered Nov 20, 2019 at 10:45

Youcef LAIDANI

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2 Comments

Andrew Over a year ago

"It's not possible to create an open size array" - But it's possible to create a new String[tab.length] assuming tab[i].length() > 4 can be true for every element

Youcef LAIDANI Over a year ago

@AndrewTobilko I agree with you

Arnaud Denoyelle · Accepted Answer · 2019-11-20 11:03:33Z

Arrays are not intended to have a dynamic size. This implies that you have to make it in 2 passes.

Count the number of words with length > 4
Insert words in the corresponding array

Here is an example in imperative style :

public class Main {

    public static void main(String[] args) throws IOException {
        String[] tab = {"Eva", "Ali", "David", "Maxime"};

        int nbLongWords = (int)Arrays.stream(tab).filter(s -> s.length() > 4).count();
        int nbShortWords = tab.length - nbLongWords;

        String[] shortWords = new String[nbShortWords];
        String[] longWords = new String[nbLongWords];

        int idxShort=0, idxLong = 0;
        for (String word : tab) {
            if(word.length() > 4) {
                longWords[idxLong++] = word;
            } else {
                shortWords[idxShort++] = word;
            }
        }
    }
}

ddon-90 · Accepted Answer · 2019-11-20 10:58:05Z

0

You can do something like this. Probably what you were trying to achieve.

int i = 0;
String[] tab = {"Eva", "Ali", "David", "Maxime"};
String[] other = new String[tab.length];

for(String elt : tab){
    if(elt.length() > 4){
        other[i++] = elt;
    }
}
for(String elt : other){
    System.out.println(elt);
}

answered Nov 20, 2019 at 10:58

ddon-90

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1 Comment

DodgyCodeException Over a year ago

This would print a lot of nulls at the end.

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