How to check how many array elements have values?

Question

How do I check how many elements have values? yes, this can also include how to check if an element has a value.

String[] Array = new String[50]; //initialization

Array[i] = "1"; // Array[0]

Array[] = "2"; // Array[1]

how can I know that 2 out of 50 elements have values?

(read about ArrayList. my app keeps crashing when I'm retrieving and displaying it.)

Mureinik · Accepted Answer · 2017-10-14 16:52:01Z

1

You could check which elements aren't null:

long numWithValue = Arrays.stream(array).filter(Objects::nonNull).count();

EDIT:
If you can't use Java 8 syntax, you can always use an old fashioned loop:

int numWithValue = 0;
for (int i = 0; i < array.length; ++i){ 
    if (array[i] != null) {
        ++numWithValue;
    }
}

edited Oct 14, 2017 at 16:52

answered Oct 14, 2017 at 15:53

Mureinik

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2 Comments

Ray Over a year ago

(Object::nonNull) : Method references are not supported at this language level (i'm using api 15) stream(arr) : cannot resolve symbol

Mureinik Over a year ago

@Ray I really suggest you use a newer version of the API. Regardless of this recommendation, check out my edited answer for a solution that would work for older versions.

Karan · Accepted Answer · 2017-10-14 16:42:26Z

0

You can use this

int count=0;
for(int i=0;i<Array.length;i++)
if(!(Array[i]==null))
count++;

count is the number of elements that have been initialised.

answered Oct 14, 2017 at 16:42

Karan

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Comments

Alex Priadko · Accepted Answer · 2017-10-14 17:31:43Z

0

 long numWithValue = arr.length - Collections.frequency(Arrays.asList(arr), null);

try this, should be compiled for 1.5 JDK

answered Oct 14, 2017 at 17:31

Alex Priadko

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