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Is it expensive to use try-catch blocks even if an exception is never thrown?

... try has almost no expense at all. Instead of doing the work of setting up the try at runtime, the code's metadata is structured at compile time such that when an exception is thrown, it now does a relatively expensive operation of walking up the stack an...
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How to download image from url

...d content is not a known image type. Check this reference on MSDN to find all format available. Here are reference to WebClient and Bitmap. share | improve this answer | fo...
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Representing and solving a maze given an image

...lection breaks are not false edges introduced by wrong threshold. In fact, all interior points of this maze are accessible from the start. Add artificial borders on the maze to make sure virtual traveler will not walk around it :) Implement breadth-first search (BFS) in your favorite language and ru...
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How do I find the duplicates in a list and create another list with them?

... @Hugo, to see the list of duplicates, we just need to create a new list called dup and add an else statement. For example: dup = [] else: dup.append(x) – Chris Nielsen Apr 29 '16 at 16:45 ...
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When should I use the Visitor Design Pattern? [closed]

...want to make the fewest possible modifications to it. The Visitor pattern allows you to move each new operation in a suitable class, and you need to extend the hierarchy's interface only once. Let's do it. First, we define an abstract operation (the "Visitor" class in GoF) which has a method for ev...
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Calling a base class's classmethod in Python

...asses, which derive from object. (at least in Python 2, but in Py3 I think all classes are new-style, IIRC) Otherwise you have to do Base.do(self, ...), I think, thereby hard-coding the name of the superclass. – David Z Jun 11 '14 at 19:29 ...
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Why does javascript replace only first instance when using replace? [duplicate]

... You need to set the g flag to replace globally: date.replace(new RegExp("/", "g"), '') // or date.replace(/\//g, '') Otherwise only the first occurrence will be replaced. share | ...
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Deep copy of a dict in python

... @BuvinJ The issue is that json.loads doesn't solve the problem for all use cases where python dict attributes are not JSON serializable. It may help those who are only dealing with simple data structures, from an API for example, but I don't think it's enough of a solution to fully answer th...
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Why is TypedReference behind the scenes? It's so fast and safe… almost magical!

...ecification, the constructs used to implement them under the hood (vararg calling convention, TypedReference type, arglist, refanytype, mkanyref, and refanyval instructions) are perfectly documented in the CLI Specification (ECMA-335) in the Vararg library. Being defined in the Vararg Library makes ...
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How to reset db in Django? I get a command 'reset' not found error

... It looks like the 'flush' answer will work for some, but not all cases. I needed not just to flush the values in the database, but to recreate the tables properly. I'm not using migrations yet (early days) so I really needed to drop all the tables. Two ways I've found to drop all ...