Enumerable.GroupBy(TSource, TKey, TElement, TResult) Method (IEnumerable(TSource), Func(TSource, TKey), Func(TSource, TElement), Func(TKey, IEnumerable(TElement), TResult), IEqualityComparer(TKey))
Silverlight
Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Key values are compared by using a specified comparer, and the elements of each group are projected by using a specified function.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Type Parameters
- TSource
The type of the elements of source.
- TKey
The type of the key returned by keySelector.
- TElement
The type of the elements in each IGrouping(TKey, TElement).
- TResult
The type of the result value returned by resultSelector.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable(TSource)
An IEnumerable(T) whose elements to group.
- keySelector
- Type: System.Func(TSource, TKey)
A function to extract the key for each element.
- elementSelector
- Type: System.Func(TSource, TElement)
A function to map each source element to an element in an IGrouping(TKey, TElement).
- resultSelector
- Type: System.Func(TKey, IEnumerable(TElement), TResult)
A function to create a result value from each group.
- comparer
- Type: System.Collections.Generic.IEqualityComparer(TKey)
An IEqualityComparer(T) to compare keys with.
Return Value
Type: System.Collections.Generic.IEnumerable(TResult)A collection of elements of type TResult where each element represents a projection over a group and its key.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(TSource). When you use instance method syntax to call this method, omit the first parameter.For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
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