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How do I correctly clone a JavaScript object?

... if you know its name, but I don't know of any way to discover it automatically. Yet another snag in the quest for an elegant solution is the problem of setting up the prototype inheritance correctly. If your source object's prototype is Object, then simply creating a new general object with {} wil...
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Private and Protected Members : C++

... Public members of a class A are accessible for all and everyone. Protected members of a class A are not accessible outside of A's code, but is accessible from the code of any class derived from A. Private members of a class A are not accessible outside of A's code, or f...
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How to correctly use the extern keyword in C

...les: on variables it doesn't instantiate the variable itself, i.e. doesn't allocate any memory. This needs to be done somewhere else. Thus it's important if you want to import the variable from somewhere else. For functions, this only tells the compiler that linkage is extern. As this is the default...
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Is explicitly closing files important?

In Python, if you either open a file without calling close() , or close the file but not using try - finally or the " with " statement, is this a problem? Or does it suffice as a coding practice to rely on the Python garbage-collection to close all files? For example, if one does this: ...
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Is there a function to make a copy of a PHP array to another?

...ewLarsson raises a point in the comments below. PHP has a special feature called "references". They are somewhat similar to pointers in languages like C/C++, but not quite the same. If your array contains references, then while the array itself is passed by copy, the references will still resolve to...
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Django MEDIA_URL and MEDIA_ROOT

... answer below; it is a better solution. – Thane Brimhall Apr 6 '16 at 14:14 is this in your app or project urls.py? ...
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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 ...
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How to check if a map contains a key in Go?

...ring) and ok will receive a bool that will be set to true if "foo" was actually present in the map evaluates ok, which will be true if "foo" was in the map If "foo" is indeed present in the map, the body of the if statement will be executed and val will be local to that scope. ...
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How to write header row with csv.DictWriter?

...ion "functionality", I'd prefer to code it myself; that way you can report ALL "extras" with the keys and values, not just the first extra key. What is a real nuisance with DictWriter is that if you've verified the keys yourself as each dict was being built, you need to remember to use extrasaction=...
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Java's L number (long) specification

It appears that when you type in a number in Java, the compiler automatically reads it as an integer, which is why when you type in (long) 6000000000 (not in integer's range) it will complain that 6000000000 is not an integer. To correct this, I had to specify 6000000000L . I just learned abo...