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Multiple columns index when using the declarative ORM extension of sqlalchemy
...my.Column class, we should use the class sqlalchemy.schema.Index to specify an index that contains multiple columns.
2 A...
Undefined symbols for architecture i386: _OBJC_CLASS_$_SKPSMTPMessage", referenced from: error
...
You can get this type of error if your class' .m file is not listed under the "Compile Sources" step of the "Build Phases" tab of your target. Normally Xcode does this for you, but sometimes it loses the plot and you need to add the .m file manually.
To d...
What's the best way to trim std::string?
...pp>
std::string str("hello world! ");
boost::trim_right(str);
str is now "hello world!". There's also trim_left and trim, which trims both sides.
If you add _copy suffix to any of above function names e.g. trim_copy, the function will return a trimmed copy of the string instead of modifying...
Given a view, how do I get its viewController?
...
I'm not sure if it would break MVC principles. At any one point, a view has only one view controller. Being able to get to it in order to pass a message back to it, should be an automatic feature, not one where you have to work to achie...
Why can't I use a list as a dict key in python?
...ists Can't Be Dictionary Keys. As explained there:
What would go wrong if you tried to use lists as keys, 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 v...
How do you build a Singleton in Dart?
...lthough what's the point of instantiating it twice? Shouldn't it be better if it threw an error when you instantiate it the second time?
– westoque
May 29 '13 at 6:30
61
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Is there a simple way to convert C++ enum to string?
...:ostream& operator<<(std::ostream& os, enum Colours c)
{
if (c >= ColoursCount || c < 0) return os << "???";
return os << colours_str[c];
}
int main()
{
std::cout << Red << Blue << Green << Cyan << Yellow << Magenta <...
How do I 'overwrite', rather than 'merge', a branch on another branch in Git?
...eckout B
$ echo 'B' > file2
$ git commit -m 'change on branch B' file2
Now, let's try the strategy option (doesn't really matter if we use theirs or ours for this explanation):
$ git merge -X ours A
$ cat file*
A
B
original
We end up with a merge of both branches' contents (branch "strategy-opt...
When to use volatile with multi threading?
...e semantics on volatile variables.
[Update for C++11]
The C++11 Standard now does acknowledge multithreading directly in the memory model and the lanuage, and it provides library facilities to deal with it in a platform-independant way. However the semantics of volatile still have not changed. v...
Concatenate two slices in Go
..., it gathers them into a new slice and passes it. I don't have first-hand knowledge of the exact mechanics, but I'd guess that this: foo(1, 2, 3, 4, 5) and this: func foo(is ...int) { just de-sugars to this: foo([]int{1, 2, 3, 4, 5}) and this: func foo(is []int) {.
– user110692...