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How to assign colors to categorical variables in ggplot2 that have stable mapping?
...maintain consistent color schemes across multiple data frames that are not all obtained by subsetting a single large data frame. Managing the factors levels in multiple data frames can become tedious if they are being pulled from separate files and not all factor levels appear in each file.
One way...
What would a “frozen dict” be?
...).
The most common reason to want such a type is when memoizing function calls for functions with unknown arguments. The most common solution to store a hashable equivalent of a dict (where the values are hashable) is something like tuple(sorted(kwargs.iteritems())).
This depends on the sorting n...
使用 C++ 处理 JSON 数据交换格式 - C/C++ - 清泛网 - 专注C/C++及内核技术
... 是比较出名的 C++ JSON 解析库。在 JSON官网也是首推的。
下载地址为：http://sourceforge.NET/projects/jsoncpp。本文使用的 jsoncpp 版本为：0.5.0。
三、jsoncpp 在 Windows 下的编译
要使用第三方源码库，第一步少不了的就是编译，将源码...
How to get the client IP address in PHP [duplicate]
...se addresses are larger than the older IPv4 addresses.
(Note that IPv6 usually uses 39 characters at most but there is also a special IPv6 notation for IPv4 addresses which in its full form can be up to 45 characters. So if you know what you are doing you can use 39 characters, but if you just want...
Python class inherits object
... so are numerous, to list some of them:
Support for descriptors. Specifically, the following constructs are made possible with descriptors:
classmethod: A method that receives the class as an implicit argument instead of the instance.
staticmethod: A method that does not receive the implicit ar...
How to watch for array changes?
...ent
}
return n;
}
});
1 Alternatively, if you'd like to target all arrays, you could override Array.prototype.push(). Use caution, though; other code in your environment may not like or expect that kind of modification. Still, if a catch-all sounds appealing, just replace myArray with Ar...
程序员之网络安全系列（六）：动态密码 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...被盗的风险：
在多个网站上使用同一密码
从互联网上下载软件
点击电子邮件中的链接
想像一下您无法访问自己的帐户及其中的内容，当别有用心的人盗取您的密码后，他们能让您无法访问自己的帐户，还可以执行以下操...
Which method performs better: .Any() vs .Count() > 0?
...le<T> sequence.
For just IEnumerable<T>, then Any() will generally be quicker, as it only has to look at one iteration. However, note that the LINQ-to-Objects implementation of Count() does check for ICollection<T> (using .Count as an optimisation) - so if your underlying data-sou...
What does the restrict keyword mean in C++?
...
A restrict-qualified pointer (or reference)...
! ...is basically a
promise to the compiler that for the
scope of the pointer, the target of the pointer will only
be accessed through that pointer (and pointers copied
from it).
In C++ compilers that support it i...
What is a plain English explanation of “Big O” notation?
...a notation "Θ" (which is a two-side bound). In my experience, this is actually typical of discussions in non-academic settings. Apologies for any confusion caused.
Big O complexity can be visualized with this graph:
The simplest definition I can give for Big-O notation is this:
Big-O notation is ...