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How to add property to a class dynamically?
...ing on. Better late than never.
You can add a property to a class dynamically. But that's the catch: you have to add it to the class.
>>> class Foo(object):
... pass
...
>>> foo = Foo()
>>> foo.a = 3
>>> Foo.b = property(lambda self: self.a + 1)
>>&...
Truncating all tables in a Postgres database
I regularly need to delete all the data from my PostgreSQL database before a rebuild. How would I do this directly in SQL?
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Parse config files, environment, and command-line arguments, to get a single collection of options
...d-line argument parsing ( argparse ). I want to write a program that does all those, and also:
11 Answers
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Compare object instances for equality by their attributes
...s:
>>> x == y
True
Note that implementing __eq__ will automatically make instances of your class unhashable, which means they can't be stored in sets and dicts. If you're not modelling an immutable type (i.e. if the attributes foo and bar may change value within the lifetime of your obje...
Objective-C : BOOL vs bool
..., you can assume that BOOL is a char. You can use the (C99) bool type, but all of Apple's Objective-C frameworks and most Objective-C/Cocoa code uses BOOL, so you'll save yourself headache if the typedef ever changes by just using BOOL.
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What is your favorite C programming trick? [closed]
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C99 offers some really cool stuff using anonymous arrays:
Removing pointless variables
{
int yes=1;
setsockopt(yourSocket, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
}
becomes
setsockopt(yourSocket, SOL_SOCKET, SO_REUSEADDR...
Using generic std::function objects with member functions in one class
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A non-static member function must be called with an object. That is, it always implicitly passes "this" pointer as its argument.
Because your std::function signature specifies that your function doesn't take any arguments (<void(void)>), you must bind the ...
How to use Boost in Visual Studio 2010
...te's answer is pretty good already, I'm going to expand on it more specifically for Visual Studio 2010 as requested, and include information on compiling in the various optional components which requires external libraries.
If you are using headers only libraries, then all you need to do is to unar...
Managing constructors with many parameters in Java
...ing to keep track of any kind of argument order, since any order of those calls will work equally well.
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Markdown and including multiple files
Is there any markdown fork that allows you to reference other files, something like an includes file? Specifically, I want to create a separate markdown file with links that I call often but not always (call this B.md), then when I link by reference in the md file I'm writing (A.md), I'd like it to ...