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Preserving order with LINQ

...p a source element by index to a result element AsEnumerable Cast Concat Select ToArray ToList Preserves Order. Elements are filtered or added, but not re-ordered. Distinct Except Intersect OfType Prepend (new in .net 4.7.1) Skip SkipWhile Take TakeWhile Where Zip (new in .net 4) Destroys O...
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Populate data table from data reader

... conn = new SqlConnection(connString); string query = "SELECT * FROM Customers"; SqlCommand cmd = new SqlCommand(query, conn); conn.Open(); SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection); DataTable dtSchema = ...
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Do I really have a car in my garage? [duplicate]

...rYears on a Vehicle without caring about the implementation. Usually, downcasting is a sign of a flawed design: do not store your vehicles all together if you need to differenciate their actual type. Note: of course the design here can be easily improved. It is just an example to demonstrate the p...
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Do I have to guard against SQL injection if I used a dropdown?

... $size = filter_input(INPUT_POST, "size", FILTER_VALIDATE_INT); echo '<select name="size">'; foreach($sizes as $i => $s) { echo '<option value="' . $i . '"' . ($i == $size ? ' selected' : '') . '>' . $s . '</option>'; } echo '</select>'; Then you can use $size in yo...
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Declare a const array

...s", "Wrongs" }; But, this still has a risk for changes, as you can still cast it back to a string[] and alter the contents, as such: ((string[]) Titles)[1] = "French"; share | improve this answe...
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How do you test functions and closures for equality?

... Simplest way is designate the block type as @objc_block, and now you can cast it to an AnyObject which is comparable with ===. Example: typealias Ftype = @objc_block (s:String) -> () let f : Ftype = { ss in println(ss) } let ff : Ftype = { sss in ...
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How to convert ‘false’ to 0 and ‘true’ to 1 in Python

... @AlbertChen: no, because numpy arrays broadcast comparisons and don't produce a boolean value. Instead, comparisons produce an array of boolean values. I'm not sure what you expect from an arrayvalue == 'true' comparison, the question I answered here is specific to a ...
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Convert int to string?

...e) * 8); BitArray[] bitArrays = BitConverter.GetBytes(value).Reverse().Select(b => new BitArray(new []{b})).ToArray(); foreach (bool bit in bitArrays.SelectMany(bitArray => bitArray.Cast<bool>().Reverse())) { builder.Append(bit ? '1' : '0'); } return builder.T...
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How do I sort an NSMutableArray with custom objects in it?

... I did this in iOS 4 using a block. Had to cast the elements of my array from id to my class type. In this case it was a class called Score with a property called points. Also you need to decide what to do if the elements of your array are not the right type, for thi...
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How do I check if a C++ std::string starts with a certain string, and convert a substring to an int?

...dy using Boost, you can do it with boost string algorithms + boost lexical cast: #include <boost/algorithm/string/predicate.hpp> #include <boost/lexical_cast.hpp> try { if (boost::starts_with(argv[1], "--foo=")) foo_value = boost::lexical_cast<int>(argv[1]+6); } c...