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LongCount Operator

Modified: 2007/01/17 05:34 by t_magennis - Categorized as: LINQ to Objects
{TOC}
Namespace:System.Linq
Assembly:System.Core.dll
Extends:IEnumerable<T>

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Introduction

The LongCount operator counts the number of elements in a sequence with a return type of Long.

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Method Signatures

// 1 - Count the number of elements in the source sequence.
public static long LongCount<TSource>(
    this IEnumerable<TSource> source)
 
// 2 - Count the number of elements that pass the predicate function.
public static long LongCount<TSource>(
    this IEnumerable<TSource> source, 
    Func<TSource, bool> predicate)



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Exceptions

Throws an ArgumentNullException if source or predicate is null.

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Pseudocode

Overload 1
If source is null, throw ArgumentNullException.
Initialize count result as 0.
Iterate over the source sequence.
count result = previous count result value + 1.
Return the count result value.


Overload 2
If source is null, throw ArgumentNullException.
If predicate is null, throw an ArgumentNullException.
Iterate the source sequence
If predicate (current element) returns true, count result = previous count result value + 1.
Return the count result value.

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Loop Count

1. The entire sequence is iterated once to evaluate the count result.

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Code Samples

TODO: Needs code sample.

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