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Applying a function to every row of a table using dplyr?
...it reflects the fact that when you're doing row wise operations you're actually working with tuples from a list of vectors (the columns in a dataframe).
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Creating an empty bitmap and drawing though canvas in Android
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This is probably simpler than you're thinking:
int w = WIDTH_PX, h = HEIGHT_PX;
Bitmap.Config conf = Bitmap.Config.ARGB_8888; // see other conf types
Bitmap bmp = Bitmap.createBitmap(w, h, conf); // this creates a MUTABLE bitmap
Canvas canvas = new Canvas(bmp);
// ready to draw on t...
How to install Xcode Command Line Tools
How do I get the command-line build tools installed with the current Xcode/Mac OS X v10.8 (Mountain Lion) or later?
13 Answ...
Is using a lot of static methods a bad thing?
I tend to declare as static all the methods in a class when that class doesn't require to keep track of internal states. For example, if I need to transform A into B and don't rely on some internal state C that may vary, I create a static transform. If there is an internal state C that I want to be ...
What is an unsigned char?
...d since I posted this, you're better off using int8_t and uint8_t if you really want to represent small integers.
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Annotating text on individual facet in ggplot2
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Typically you'd do something like this:
ann_text <- data.frame(mpg = 15,wt = 5,lab = "Text",
cyl = factor(8,levels = c("4","6","8")))
p + geom_text(data = ann_text,label = "Text")
It should work without specifying the factor variable comple...
What is the maximum recursion depth in Python, and how to increase it?
...mple context manager like this:
import sys
class recursionlimit:
def __init__(self, limit):
self.limit = limit
self.old_limit = sys.getrecursionlimit()
def __enter__(self):
sys.setrecursionlimit(self.limit)
def __exit__(self, type, value, tb):
sys.setr...
Iterate a list as pair (current, next) in Python
...(b, None)
return itertools.izip(a, b)
How this works:
First, two parallel iterators, a and b are created (the tee() call), both pointing to the first element of the original iterable. The second iterator, b is moved 1 step forward (the next(b, None)) call). At this point a points to s0 and b...
VS Debug调试模式下内存泄露检测原理 - C/C++ - 清泛网 - 专注C/C++及内核技术
...T宏定义了malloc、realloc，如下：
#define malloc(s) _malloc_dbg(s, _NORMAL_BLOCK, __FILE__, __LINE__)
#define calloc(c, s) _calloc_dbg(c, s, _NORMAL_BLOCK, __FILE__, __LINE__)
#define realloc(p, s) _realloc_dbg(p, s, _NORMAL_BLOCK, __FILE__, __LINE__)
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关于php的socket初探 - PHP - 清泛IT论坛，有思想、有深度
...塞的古老模型：属于同步阻塞 IO 模型，代码如下：
socket_server.php
<?php
/**
* SocketServer Class
* By James.Huang <shagoo#gmail.com>
**/
set_time_limit(0);
class SocketServer
{
private stati...