CODEWITHSUNDEEP
c#linqlist
deadfish
deadfish

Reputation: 12304

Count elements in each array of a List<Array>

How can I count elements that are equal to 0 in each array of a list?

I have a list List<byte[]> piks. I would like to count in each byte[] how many elements are with equal to 0.

I tried a few ways: 

from c in piksle_lista_tablic[84] 
where (c.Equals(0)) 
select c

or 

piksle_lista_tablic[84].Count(n => n == 0)

and I always get the error Expression cannot contain lambda expressions.

For example: piks[1] is an array containing 1156 items, and I would like to know how many specific elements are in that array.

PS: Can i use Linq in watch window?

Upvotes: 2

Views: 2557

Answers (4)

Rune FS
Rune FS

Reputation: 21742

var results = from arr in piks
              select arr.Where(b=>b==0).Count()

that code will iterate the list of array and for each array find the elements equalling zero and return an IEnumerable with the counts for each array. I like the where count more than the Count(selector) but that a matter of taste. I doubt there's going to be noticeable difference performancewise

to you ps 1 yes you can use linq while debugging but it's generally a pain because a linq statement is one statement chopping it up in methods can sometimes help while debugging but I dislike writing code for the sake of the debugger.

EDIT As per your comment: No you cannot use Lambda in the watch window. You can use Linq in the watch window but only as method calls and only with named functions

Upvotes: 5

Miguel Angelo
Miguel Angelo

Reputation: 24192

If you want to count the global total, you can do this:

piks.SelectMany(p => p).Count(p => p == 0);

For each array you can do this:

piks.Select(p => p.Count(p => p == 0));

Upvotes: 1

Otiel
Otiel

Reputation: 18743

List<byte[]> piks;
// Fill piks...
int zeroValuesCount = 0;
foreach (var pik in piks) {
    zeroValuesCount += pik.Count(x => x == 0);
}

Upvotes: 1

Mark Byers
Mark Byers

Reputation: 838166

Try this:

var zero_counts = piks.Select(p => p.Count(c => c == 0));

ps1. can i try use linq while debug?

Visual Studio doesn't support lambda expressions in the watch window.

Upvotes: 4

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