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    <p>You have a very nasty problem that arises from mutating an outer variable to the lambda expression. The problem is this: if you try to iterate <code>eligibleVoters</code> twice (<code>foreach(var voter in eligibleVoters) { Console.WriteLine(voter.Name); }</code> and immediately after (<code>foreach(var voter in eligibleVoters) { Console.WriteLine(voter.Name); }</code>) you will not see the same output. That is just not right from a functional programming perspective.</p> <p>Here is an extension method that will accumulate until some condition on the accumulator is true:</p> <pre><code>public static IEnumerable&lt;T&gt; TakeWhileAccumulator&lt;T, TAccumulate&gt;( this IEnumerable&lt;T&gt; elements, TAccumulate seed, Func&lt;TAccumulate, T, TAccumulate&gt; accumulator, Func&lt;TAccumulate, bool&gt; predicate ) { TAccumulate accumulate = seed; foreach(T element in elements) { if(!predicate(accumulate)) { yield break; } accumulate = accumulator(accumulate, element); yield return element; } } </code></pre> <p>Usage:</p> <pre><code>var eligibleVoters = voters.TakeWhileAccumulator( 0, (votes, p) =&gt; votes + p.Voices, i =&gt; i &lt; 300 ); </code></pre> <p>Thus the above says accumulate voices while we have accumulated less than 300 votes.</p> <p>Then with:</p> <pre><code>foreach (var item in eligibleVoters) { Console.WriteLine(item.Name); } Console.WriteLine(); foreach (var item in eligibleVoters) { Console.WriteLine(item.Name); } </code></pre> <p>Output is:</p> <pre><code>Alice Bob Catherine Alice Bob Catherine </code></pre>
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    1. PODoes this code really cause an "access to modified closure" problem?
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    1. USjason
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    1. PODoes this code really cause an "access to modified closure" problem?
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    1. COIs there a good way to handle this?
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    2. COYes, write a different extension method. See my edit.
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