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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)
...
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...
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.
...
What is the __del__ method, How to call it?
I am reading a code. There is a class in which __del__ method is defined. I figured out that this method is used to destroy an instance of the class. However, I cannot find a place where this method is used. The main reason for that is that I do not know how this method is used, probably not like ...
How to find out what type of a Mat object is with Mat::type() in OpenCV
...st.
string type2str(int type) {
string r;
uchar depth = type & CV_MAT_DEPTH_MASK;
uchar chans = 1 + (type >> CV_CN_SHIFT);
switch ( depth ) {
case CV_8U: r = "8U"; break;
case CV_8S: r = "8S"; break;
case CV_16U: r = "16U"; break;
case CV_16S: r = "16S"; break;...
Command-line Unix ASCII-based charting / plotting tool
...ne, not bar, plots ?)
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import division
import numpy as np
__version__ = "2015-01-02 jan denis"
#...............................................................................
def onelineplot( x, chars=u"▁▂▃▄▅▆▇█", se...