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Why can't I use a list as a dict key in python?

..., with the hash as, say, their memory location? It can be done without really breaking any of the requirements, but it leads to unexpected behavior. Lists are generally treated as if their value was derived from their content's values, for instance when checking (in-)equality. Many would - underst...
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Difference between MEAN.js and MEAN.io

... that there are two different stacks with either their own website and installation methods: mean.js and mean.io. So I came up asking myself this question: "Which one do I use?". ...
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What are rvalues, lvalues, xvalues, glvalues, and prvalues?

...e they needed? Probably not if we wish to forfeit the new features. But to allow better optimization we should probably embrace them. Quoting n3055: An lvalue (so-called, historically, because lvalues could appear on the left-hand side of an assignment expression) designates a function or an obj...
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Why use prefixes on member variables in C++ classes

...before a capital letter in a word is reserved. For example: _Foo _L are all reserved words while _foo _l are not. There are other situations where leading underscores before lowercase letters are not allowed. In my specific case, I found the _L happened to be reserved by Visual C++ 2005 and ...
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Determine the type of an object?

...object, and isinstance() to check an object’s type against something. Usually, you want to use isistance() most of the times since it is very robust and also supports type inheritance. To get the actual type of an object, you use the built-in type() function. Passing an object as the only param...
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Get model's fields in Django

Given a Django model, I'm trying to list all of its fields. I've seen some examples of doing this using the _meta model attribute, but doesn't the underscore in front of meta indicate that the _meta attribute is a private attribute and shouldn't be accessed directly? ... Because, for example, the ...
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Scala: List[Future] to Future[List] disregarding failed futures

...ures to a Future of List. I'm using Playframework, so ultimately, what I really want is a Future[Result] , but to make things simpler, let's just say Future[List[Int]] The normal way to do this would be to use Future.sequence(...) but there's a twist... The list I'm given usually has around 10-...
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What does a just-in-time (JIT) compiler do?

What does a JIT compiler specifically do as opposed to a non-JIT compiler? Can someone give a succinct and easy to understand description? ...
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What is the worst gotcha in C# or .NET? [closed]

...return MyVar; } } Blammo. Your app crashes with no stack trace. Happens all the time. (Notice capital MyVar instead of lowercase myVar in the getter.) share | improve this answer | ...
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Proper way to make HTML nested list?

... same applies to HTML5 ol. The description list (HTML5 dl) is similar, but allows both dt and dd elements. More Notes: dl = definition list. ol = ordered list (numbers). ul = unordered list (bullets). share | ...