Android java cannot remove empty element

Question

I want to remove all empty element.. I use code below this, but did not working..

sejarahToken.removeAll(Collections.singleton(""));
    sejarahToken.removeAll(Arrays.asList(""));
    for (String st : sejarahToken) {
        writingFile(st);
    }

same as using this code:

 sejarahToken.removeAll(Collections.singleton(null));
 sejarahToken.removeAll(Arrays.asList(null,""));

Here's output the sejarahToken arraylist on txt file.. there are still empty values:

Leonardo
da
Vinci
dari
Italia
dan
Otto
Lilienthal
dari
Jerman
telah
mendahuluinya


Tetapi
ternyata
jauh
sebelumnya
semua
sudah
didahului
oleh
seorang

Perhaps you have entries which are just whitespace? It doesn't help that we don't know what writingFile looks like. Have you tried debugging through the code to see what the list looks like after the call to removeAll? — Jon Skeet
– Jon Skeet, Commented Mar 31, 2015 at 16:28
thank you.. i just realize.. all because of whitespace. thats why i can't remove using blankspace or null — Lita
– Lita, Commented Mar 31, 2015 at 17:33
I just knew.. I'm very glad you're giving me a warning and fix the question. I will remember that. — Lita
– Lita, Commented Apr 6, 2015 at 23:38

Kennedy Oliveira · Accepted Answer · 2015-03-31 16:32:42Z

2

You can use the following code snippet to remove if there are empty strings or strings with whitespaces.

final Iterator<String> iterator = sejarahToken.iterator();

while (iterator.hasNext()) {
  final String e = iterator.next();

  if (e == null || e.trim().isEmpty())
    iterator.remove();
}

answered Mar 31, 2015 at 16:32

Kennedy Oliveira

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Comments

Fahim · Accepted Answer · 2015-03-31 16:48:42Z

1

Use this

al.removeAll(Arrays.asList(null,""));

This will remove all elements that are null or equals to "" in your List.

edited Mar 31, 2015 at 16:48

answered Mar 31, 2015 at 16:31

Fahim

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1 Comment

laubed Over a year ago

The second code won't work with whitespaces or empty strings. Better go the first way

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