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Using a dispatch_once singleton model in Swift
...variables), and is thread safe by the definition of let. This is now officially recommended way to instantiate a singleton.
Class constants were introduced in Swift 1.2. If you need to support an earlier version of Swift, use the nested struct approach below or a global constant.
Nested struct
cl...
How to create a unique index on a NULL column?
...rver 2005. I want to constrain the values in a column to be unique, while allowing NULLS.
4 Answers
...
Check synchronously if file/directory exists in Node.js
... Note that fs.exists() is deprecated, but fs.existsSync() is not. (The
callback parameter to fs.exists() accepts parameters that are
inconsistent with other Node.js callbacks. fs.existsSync() does not
use a callback.)
You've specifically asked for a synchronous check, but if you can use an ...
内存调试技巧：C 语言最大难点揭秘 - C/C++ - 清泛网 - 专注C/C++及内核技术
...他许多通用语言（如 Java™、Ruby、Haskell、C#、Perl、Smalltalk 等），每种语言都有众多的爱好者和各自的优点。但是，从计算角度来看，每种编程语言优于 C 或 C++ 的主要优点都与便于内存管理密切相关。与内存相关的编程是如...
How to change a table name using an SQL query?
...
Use sp_rename:
EXEC sp_rename 'Stu_Table', 'Stu_Table_10'
You can find documentation on this procedure on MSDN.
If you need to include a schema name, this can only be included in the first parameter (that is, this cannot be use...
What is the advantage of using forwarding references in range-based for loops?
...or<bool> v(10);
for (auto&& e : v)
e = true;
}
All that being said, I wouldn't code this way unless you knew you needed to satisfy such a use case. I.e. I wouldn't do this gratuitously because it does cause people to wonder what you're up to. And if I did do it, it woul...
reducing number of plot ticks
...
Alternatively, if you want to simply set the number of ticks while allowing matplotlib to position them (currently only with MaxNLocator), there is pyplot.locator_params,
pyplot.locator_params(nbins=4)
You can specify specific axis in this method as mentioned below, default is both:
# To...
Is it possible to insert multiple rows at a time in an SQLite database?
...blename'
SELECT 'data1' AS 'column1', 'data2' AS 'column2'
UNION ALL SELECT 'data1', 'data2'
UNION ALL SELECT 'data1', 'data2'
UNION ALL SELECT 'data1', 'data2'
a note on performance
I originally used this technique to efficiently load large datasets from Ruby on Rails. However, as Jaime...
How to sort with a lambda?
...nclude <iostream>
#include <sstream>
struct Foo
{
Foo() : _i(0) {};
int _i;
friend std::ostream& operator<<(std::ostream& os, const Foo& f)
{
os << f._i;
return os;
};
};
typedef std::vector<Foo> VectorT;
std::string ...
How to get a list of properties with a given attribute?
...rties that have the attribute MyAttribute . The attribute is marked with AllowMultiple = false , like this:
6 Answers
...