Hooked on LINQ

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Namespace:System.Linq
Assembly:System.Core.dll
Extends:IEnumerable<T>

Back to Standard Query Operator Index


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Introduction

The ElementAtOrDefault operator returns the element at a given index in a sequence, or a default value if the index is out of range.

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Method Signatures

public static TSource ElementAtOrDefault<TSource>(
    this IEnumerable<TSource> source, 
    int index)



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Exceptions

Throws an ArgumentNullException if source is null.


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Pseudo-code

If source is null, throw an ArgumentNullException.
If index < 0 return default(TSource);
If the source sequence implements IList<T>
If index >= source.Count then return default(TSource);
Return source[index]. (performance optomization)
Else Iterate the source sequence.
Skip index times. Return default(TSource); if there aren't enough elements.
Return the current element.

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Loop Count

< 1. If the sequence is an IList, then it is index accessed which is optomized for each collection type. If the sequence is not an IList, the number of elements skipped is equal to the index value.

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Code Samples

TODO:Needs code sample.

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