How to Count the Number of Elements That Match a Condition with Linq

How to count the number of elements that match a condition with LINQ

int divisor = AllMyControls.Where(p => p.IsActiveUserControlChecked).Count()

or simply

int divisor = AllMyControls.Count(p => p.IsActiveUserControlChecked);

Since you are a beginner, it would be worthwhile to take a look at Enumerable documentation

Count elements with a condition in a sublist with linq

_eventManager.QueryEvents().Where(x => x.StartTime > DateTime.Today)
                           .SelectMany(x => x.EventUsers)
                           .Count(z => z.UserId == userId && !z.HasResponded)

Linq Get count from multiple where condition

var result = records.GroupBy(x => x.Date)
                    .Select(x => new { Date = x.Key, Count = x.Count() });

is what you want

result will now have a list of dates and count.

if you want a specific value then like this:

var result = records.Where(x => x.Record == -1).
                    .GroupBy(x => x.Date)
                    .Select(x => new { Date = x.Key, Count = x.Count() });

To group by the date and not the date time use the date property of the object in the GroupBy statement

                    .GroupBy(x => x.Date.Date)

How can i use Count with condition in LINQ

You need to pass a lambda that takes the entity and returns a bool, like this

var id = Session["CustomerID"];
var recordcount = db.EventParticipants.Where(x => x.CustomerID == id).Count();

Note you'll also want to put the id into a separate variable as EF will not be able to translate Session into SQL.

Linq Query with a where condition - count items

How about this:

query = query.Where(item => context.Table
                                   .Count(t => t.amount == item.Amount) >= 10);

Or to reduce the number of round-trips:

var counts = context.Table
                    .GroupBy(t => t.amount)
                    .Select(g => new {amount = g.Key, count = g.Count()});

query = from q in query
        join c in counts
        on q.amount equals c.amount
        where c.count >= 10
        select q;

LinQ query that counts the number of elements in a list of objects in another list of objects

if you select each family, then return the count of males in it, you would get an enumerable of counts - e.g {0,1,0,3,2,1} - you can then simply Sum those counts

  ListOfFams.Select(f => f.persons.Where(p => p.gender == gender.male).Count()).Sum();

//to reject nulls

ListOfFams.
    Where(f => f != null && f.persons != null).
    Select(f => f.persons.
    Where(p => p != null && p.gender == gender.male).
    Count()).
    Sum();

Linq count condition in query

Perhaps the LINQ Count function is called for:

var query = (from u in users
     where u.Roles.Any(r => r.RoleId == role.Id)
     from t in u.ProjectTasks.Where(x => x.Users.Any(user => user.Id == u.Id)).DefaultIfEmpty()
     where ((u.ProjectTasks.Count() == 0) || u.ProjectTasks.Count(z => z.Status == Status.Active || z.Status == Status.Testing) <= 3)
     select new { User = u } into Users
     group Usersby Users.User).ToList(); 

For examples of usages: http://www.csharp-examples.net/linq-count/

count objects that meet certain condition in List-collection

There's is a count method using a predicate : see Enumerable.Count Method (IEnumerable, Func)

Note that this method is an extension method and you can use it only if you add a reference to the System.Linq namespace.

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