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POWhat's the pattern to use for iterating over associated sets of values?
 

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  1. POWhat's the pattern to use for iterating over associated sets of values?
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    <p>It's pretty common - especially as you try to make your code become more data-driven - to need to iterate over associated collections. For instance, I just finished writing a piece of code that looks like this:</p> <pre><code>string[] entTypes = {"DOC", "CON", "BAL"}; string[] dateFields = {"DocDate", "ConUserDate", "BalDate"}; Debug.Assert(entTypes.Length == dateFields.Length); for (int i=0; i&lt;entTypes.Length; i++) { string entType = entTypes[i]; string dateField = dateFields[i]; // do stuff with the associated entType and dateField } </code></pre> <p>In Python, I'd write something like:</p> <pre><code>items = [("DOC", "DocDate"), ("CON", "ConUserDate"), ("BAL", "BalDate")] for (entType, dateField) in items: # do stuff with the associated entType and dateField </code></pre> <p>I don't need to declare parallel arrays, I don't need to assert that my arrays are the same length, I don't need to use an index to get the items out.</p> <p>I feel like there's a way of doing this in C# using LINQ, but I can't figure out what it might be. Is there some easy method of iterating across multiple associated collections?</p> <p><strong>Edit:</strong></p> <p>This is a little better, I think - at least, in the case where I have the luxury of zipping the collections manually at declaration, and where all the collections contain objects of the same type:</p> <pre><code>List&lt;string[]&gt; items = new List&lt;string[]&gt; { new [] {"DOC", "DocDate"}, new [] {"CON", "ConUserDate"}, new [] {"SCH", "SchDate"} }; foreach (string[] item in items) { Debug.Assert(item.Length == 2); string entType = item[0]; string dateField = item[1]; // do stuff with the associated entType and dateField } </code></pre>
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    1. USRobert Rossney
    1. USRobert Rossney
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    1. COWhy would one want a "more compressed but less readable" way to write something instead of defining a struct or a class?
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      1. USHamid
    2. COIf you have 30 or 40 pairs of values, having to write the same member names 30 or 40 times doesn't make the code *more* readable.
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      1. POWhat's the pattern to use for iterating over associated sets of values?
      1. USRobert Rossney
 

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