LINQ: How to perform a conditional sum? - linq

Question

I have a LINQ Query that creates a new type that contains a days of week and a sum of hours worked.
My current (incorrect query) looks like this:
var resultSet = (from a in events
group a by a.Start.DayOfWeek into g
select new DaySummary
{
day = g.Key.ToString(),
hoursWorked = g.Any(p => p.Title == "Lunch") ? 0 :
Math.Round((g.Sum(
p => (Decimal.Parse((p.End - p.Start).TotalMinutes.ToString()))) / 60), 2)
}).ToList();
Hopefully you can see what Im trying to do. The Any method is not having the effect I'd like however. Basically I want to to sum up the hours worked, but if the title was "lunch" I want it to add 0.
The logic of this is just a little beyond me at the moment.
UPDATE
Ok, Im an idiot. Changes the query to this and it now works. Sorry.
var resultSet = (from a in events
group a by a.Start.DayOfWeek into g
select new DaySummary
{
day = g.Key.ToString(),
hoursWorked = Math.Round((g.Where(p => p.Title !="Lunch").
Sum(p => (Decimal.Parse((p.End - p.Start).TotalMinutes.ToString()))) / 60), 2)
}).ToList();

Answer 1

It seems each group is a sequence of 'periods' and you just want to ignore any 'lunch' periods in each calculation. In that case you just need to remove these from the sum using Where.
var hours = events
.GroupBy(e => e.Start.DayOfWeek)
.Select(g => new DaySummary {
day = g.Key.ToString(),
hoursWorked = Math.Round(
g.Where(p => p.Title != "Lunch")
.Sum(pd => (Decimal.Parse((pd.End - pd.Start).TotalMinutes.ToString())) / 60), 2)
}).ToList();