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    <p>Most of these entities take only a single character, yet you are storing them as strings. The reference pointer to those string <em>alone</em> is going to take <em>at least</em> twice as much space (in case of UTF8 likely 4-8 times as much). Then there is the overhead of keeping a hash table structured for the dictionary.</p> <p>The <code>List&lt;&gt;</code> in itself should be really efficient storage wise (it uses an array internally)</p> <p><strong>Room for improvement</strong>:</p> <ul> <li>you could use <code>List&lt;char&gt;</code> or <code>char[]</code> instead of <code>List&lt;string&gt;</code> if you know that the fields will fit</li> <li>you could use <code>struct Field { char a,b/*,...*/; }</code> and List instead of List if you need more than 1 character per field</li> <li><p>You could <strong>forgo the eager field extraction</strong> [&lt;-- recommended]: </p> <pre><code> var dict = File.ReadAllLines(file) .ToDictionary(line =&gt; line.Split(',')[27]); </code></pre> <p>This gives you the opportunity to access the compareElements on demand:</p> <pre><code> string[] compareElements = dicts["key27"].Split(',')/*.Take(24).ToArray()*/; </code></pre> <p>This is a classic example of runtime/storage cost trade-off</p></li> </ul> <p><strong>Edit</strong> an obvious hybrid would be:</p> <pre><code>struct AllCompareElements { public char field1, field2, ... field24; // perhaps: public char[2] field13; // for the exceptional field that is longer than 1 character } </code></pre> <p>Happily employ Resharper to implement <code>Equals</code>, <code>GetHashCode</code>, <code>IEquatable&lt;AllCompareElements&gt;</code>, <code>IComparable&lt;AllCompareElements&gt;</code></p>
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    1. POIs my dictionary size normal?
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    1. POIs my dictionary size normal?
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    1. COIf I used char[] I would have to remove the commas. Not a problem, just saying but its an overhead and the string.Split is doing it for me already
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    2. CO@Jon: You missed the point. I meant store the result of split in List<char>, not List<string>: `line.Split(',').Take(24).Select(s => s[0]);`. Not only is a char usually smaller than a string, most importantly, char is a `ValueType`, string is a `reference type`. Especially when storing valuetypes in a generic `List<>` the storage requirements get drastically optimized.
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    3. COI'll look into that. I don't see the benefit of doing the ReadAllLines as I only need to store the 24 in the dictionary so your example would have me then find the item in the dictionary and then replace the contents
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