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How to decorate a class?
...r specific scenario, YMMV :-)
What you're thinking of is a metaclass. The __new__ function in a metaclass is passed the full proposed definition of the class, which it can then rewrite before the class is created. You can, at that time, sub out the constructor for a new one.
Example:
def substitu...
Are list-comprehensions and functional functions faster than “for loops”?
...(<the code object for `[x for x in range(10)]`>)
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 12 (to 21)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
...
What's the difference between echo, print, and print_r in PHP?
I use echo and print_r much, and almost never use print .
11 Answers
11
...
Comparing strings with == which are declared final in Java
...llowing byte code:
Code:
0: ldc #2; //String str
2: astore_1
3: ldc #3; //String ing
5: astore_2
6: new #4; //class java/lang/StringBuilder
9: dup
10: invokespecial #5; //Method java/lang/StringBuilder."<init>":()V
13: aload_1
14: invo...
关于php的socket初探 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...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 static $socket;
function SocketServer($port)
{ ...
Checking images for similarity with OpenCV
...e the L2 relative error between images.
double errorL2 = norm( A, B, CV_L2 );
// Convert to a reasonable scale, since L2 error is summed across all pixels of the image.
double similarity = errorL2 / (double)( A.rows * A.cols );
return similarity;
}
else {
//Images have a differen...
What is SYSNAME data type in SQL Server?
...stored procedures etc within SQL Server.
For example, by executing Exec sp_help 'sys.tables' you will see that the column name is defined as sysname this is because the value of this is actually an object in itself (a table)
I would worry too much about it.
It's also worth noting that for those p...
Approximate cost to access various caches and main memory?
...opy of a line. But remember, Intel uses MESIF (en.wikipedia.org/wiki/MESIF_protocol) for NUMA, AMD uses MOESI. I think within a single socket, though, MESIF isn't really a thing because data comes from L3, not core->core. So it's probably more relevant for L3 cache->cache transfers across s...
method of iterating over sqlalchemy model's defined columns?
...and copy methods to a couple of models. I can't just iterate over the obj.__dict__ since it contains a lot of SA specific items.
...
App Inventor 2 上传文件和图片到服务器教程 · App Inventor 2 中文网
...端：upload.php（接收 PostFile）
方案二服务器端：upload_base64.php（接收 Base64 数据）
服务器端代码（Node.js 与 Python）
Node.js 对应实现
Python 对应实现
上传进度显示
方式一：显示加载对话框
...