Suppose this is my member class
class Member
{
public string CategoryId { get; set; }
public string MemberName { get; set; }
public int Distance { get; set; }
}
And, this is list.
var list = new List<Member>();
list.Add(new { CategoryId = "01", MemberName="andy" Distance=3});
list.Add(new { CategoryId = "02", MemberName="john" Distance=5});
list.Add(new { CategoryId = "01", MemberName="mathew" Distance=7});
list.Add(new { CategoryId = "03", MemberName="bakara" Distance=2});
Can anyone please suggest the logic/ linq query to get the List having distinct/unique categoryID with Shortest distance.
The output
should be :
list.Add(new { CategoryId = "01", MemberName="andy" Distance=3});
list.Add(new { CategoryId = "02", MemberName="john" Distance=5});
list.Add(new { CategoryId = "03", MemberName="bakara" Distance=2});
This should give you what you need:
var grouped = list.GroupBy(item => item.CategoryId);
var shortest = grouped.Select(grp => grp.OrderBy(item => item.Distance).First());
It first groups the items with the same CategoryId
, then selects the first from each group (ordered by Distance
).
This is similar to those above, however it is technically a one liner for those interested....
var queryResult= (from l in list
select new Member()
{
CategoryId = l.CategoryId ,
MemberName = l.MemberName
Distance = l.Distance
}).GroupBy(x=>x.CatagoryId).Select(z=>z.OrderBy(i=>i.Distance).First()).ToList();
You can use the following code:
List<Member> sourceList = new List<Member>();
IEnumerable<Member> result =
(sourceList as IEnumerable<Member>)
.Distinct()
.OrderBy(value => value.CategoryId);
Group the list into categories, then order each grouping by distance, taking the first item (the lowest distance). Project the results into a new Member
collection.
var query = from member in list
group member by member.CategoryId into memberGrouping
let groupedMember = memberGrouping.OrderBy (mg => mg.Distance).First()
select new Member()
{
CategoryId = memberGrouping.Key,
MemberName = groupedMember.MemberName,
Distance = groupedMember.Distance
};
try this
var distinctIds = list.Distinct(item => item.CategoryId).ToList();
var newList = new List<Member>();
foreach(var id in distinctIds){
newList.Add(list.Where(item => item.CategoryId == id).Min(item => item.Distance))
}
newList.OrderBy(item => item.CategoryId);
class Member {
public string CategoryId {get; set;}
public string MemberName{get; set;}
public int Distance{get; set;}
}
var list = new List<Member>();
list.Add(new Member{ CategoryId = "01", MemberName="andy", Distance=3});
list.Add(new Member{ CategoryId = "02", MemberName="john", Distance=5});
list.Add(new Member{ CategoryId = "01", MemberName="mathew", Distance=7});
list.Add(new Member{ CategoryId = "03", MemberName="bakara", Distance=2});
var query = list.GroupBy(member => member.CategoryId).Select(x=>x.OrderBy(y=>y.Distance).First());
This also works, if you do not require items ordered by (little modified Kjartan's answer )
var grouped = list.GroupBy(item => item.CategoryId).ToList();
var shortest = grouped.Select(grp => grp.OrderBy(item => item.Distance).First());
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