CODEWITHSUNDEEP
javaarraysif-statementfor-loop
Ruben
Ruben

Reputation: 65

Removing empty element from Array(Java)

I'm trying to remove the empty element from the array by copying the existing element to a new array. However, initialization of the new array is causing my return value to be null even when I initialize it within the for loop.

public String[] wordsWithout(String[] words, String target) {
    for(int i = 0; i < words.length; i = i +1){
        String store[] = new String[words.length];
        if (words[i] == target){
            words[i] ="";
        }
        else if(words[i] != target){
            words[i] = store[i];
        }       
    }
    return words;
}

Upvotes: 5

Views: 12161

Answers (5)

Joe ONeil
Joe ONeil

Reputation: 130

Array are immutable so the size stays the same you need to create a new Array So if you create a new Array base on the Size of the Old array you will still have null elements

If you want to use arrays only you need to count the non null elements in the array to get the size of the new Array. It just easier to use a List/ArrayList

public String[] wordsWithout(String[] words, String target) {
    List<String> tempList=new ArrayList<String>();
    for(int i = 0; i < words.length; i = i +1){

        if (words[i]!=null||words[i].trim().length()>0){
            tempList.add(words[i]);
        }

    }
    return (String[]) tempList.toArray();
}

Upvotes: 2

Abdul Malik
Abdul Malik

Reputation: 317

To check the equality use .equals() method i-e string1.equals(string2) and to check non-equality you can use the same method but with not(!) operator i-e. !string1.equals(string2). You should declare the store array outside the loop because in each iteration it makes a new object onamed store. In the else condition do this store[i] = words[i].

Upvotes: 1

J&#233;r&#244;me
J&#233;r&#244;me

Reputation: 1254

I'm actually not sure what you want to achieve but if you want to remove an empty String out of your array you can do it with streams and filters in java 8 like this:

String[] objects = Arrays.stream(new String[]{"This","", "will", "", "", "work"}).filter(x -> !x.isEmpty()).toArray(String[]::new);

Upvotes: 8

nits.kk
nits.kk

Reputation: 5336

There are few things Which I am putting as points below. Hope you will get help from this.

  1. String store[] = new String[words.length] instantiates an array of Strings but It does not instantiate any of the elements with any non null value. Default value is null so this is an array of null Strings.

  2. (words[i] != target) should be replaced with

    (!words[i].equals(target))

Upvotes: 0

Andremoniy
Andremoniy

Reputation: 34920

You shouldn't compare strings using == operator. This is incorrect, because strings are objects. Use .equals() method instead, this should fix your problem.

Rest part of your code is quite confusing, it's hard to understand what you are trying to achieve: you create new string array store each time in loop iterations, and then assign its null (by default) values to words[i]. You should elaborate your code and algorithm.

Upvotes: 0

Related Questions