C# Linq Combine multiple sequences by key
I have two IList<Traffic>
I need to combine.
Traffic is a simple class:
class Traffic
{
long MegaBits;
DateTime Time;
}
Each IList
holds the same Times, and I need a single IList<Traffic>
, where I have summed up the MegaBits, but kept the Time as key.
Is this possible using Linq ?
EDIT:
I forgot to mention that Time isn't necessarily unique in any list, multiple Traffic
instances may have the same Time.
Also I might run into X lists (more than 2), I should had mentioned that as well - sorry :-(
EXAMPLE:
IEnumerable<IList<Traffic>> trafficFromDifferentNics;
var combinedTraffic = trafficFromDifferentNics
.SelectMany(list => list)
.GroupBy(traffic => traffic.Time)
.Select(grp =>开发者_C百科 new Traffic { Time = grp.Key, MegaBits = grp.Sum(tmp => tmp.MegaBits) });
The example above works, so thanks for your inputs :-)
this sounds more like
var store = firstList.Concat(secondList).Concat(thirdList)/* ... */;
var query = from item in store
group item by item.Time
into groupedItems
select new Traffic
{
MegaBits = groupedItems.Sum(groupedItem => groupedItem.MegaBits),
Time = groupedItems.Key
};
or, with your rework
IEnumerable<IList<Traffic>> stores;
var query = from store in stores
from item in store
group item by item.Time
into groupedItems
select new Traffic
{
MegaBits = groupedItems.Sum(groupedItem => groupedItem.MegaBits),
Time = groupedItems.Key
};
You could combine the items in both lists into a single set, then group on the key to get the sum before transforming back into a new set of Traffic
instances.
var result = firstList.Concat(secondList)
.GroupBy(trf => trf.Time, trf => trf.MegaBits)
.Select(grp => new Traffic { Time = grp.Key, MegaBits = grp.Sum()});
That sounds like:
var query = from x in firstList
join y in secondList on x.Time equals y.Time
select new Traffic { MegaBits = x.MegaBits + y.MegaBits,
Time = x.Time };
Note that this will join in a pair-wise fashion, so if there are multiple elements with the same time in each list, you may not get the results you want.
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