CODEWITHSUNDEEP
linq
Jynn
Jynn

Reputation: 287

linq query comparing Dates within a list

I have a list object, lets call it "Parent". Within Parent a have several "Child" objects. Within "Child", I have a DateTime property called StartDay.

I would like to run a linq query that will examine Parent and return the day of the week of StartDay if it is always the same day of the week. If for example we have some StartDay's on wednesday and some on tuesday it will return "Variable".

Upvotes: 0

Views: 37

Answers (2)

stovroz
stovroz

Reputation: 7095

parents.Where(x => x.Children.Any())
  .Select(x => new { Parent = x, StartDays = x.Children.Select(y => y.StartDay).Distinct() })
  .Select(x => new { x.Parent, StartDay = x.StartDays.Count() == 1 ? x.StartDays.Single().ToString() : "Variable" });

Upvotes: 0

Tim Schmelter
Tim Schmelter

Reputation: 460380

If you want to check if all parents' children have the same StartDay.DayOfWeek:

bool allOnSameDay = Parent.All(p => {
     var firstChildDayOfWeek = p.Children.First().StartDay.DayOfWeek;
     return p.Children.All(c => c.StartDay.DayOfWekk == firstChildDayOfWeek);
})

Upvotes: 1

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