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Adding information to an exception?
...essage + ' happens at %s' % arg1)
bar('arg1')
Traceback (most recent call last):
File "test.py", line 13, in <module>
bar('arg1')
File "test.py", line 11, in bar
raise type(e)(e.message + ' happens at %s' % arg1)
IOError: Stuff happens at arg1
Update 1
Here's a slight modif...
What is the difference between old style and new style classes in Python?
...(x) is always <type
'instance'>.
This reflects the fact that all old-style instances, independently of
their class, are implemented with a single built-in type, called
instance.
New-style classes were introduced in Python 2.2 to unify the concepts of class and type.
A new-s...
How do I get the opposite (negation) of a Boolean in Python?
...ful if you want to use a function that requires a predicate-function or a callback.
For example map or filter:
>>> lst = [True, False, True, False]
>>> list(map(operator.not_, lst))
[False, True, False, True]
>>> lst = [True, False, True, False]
>>> list(filter...
Dynamic variable names in Bash
...Fgilrtux] [-p] [name[=value] ...]. You might double-check that you are actually running 4.x and not 3.2.
– chepner
Dec 2 '13 at 16:08
5
...
Is generator.next() visible in Python 3?
...son for this is consistency: special methods like __init__() and __del__() all have double underscores (or "dunder" in the current vernacular), and .next() was one of the few exceptions to that rule. This was fixed in Python 3.0. [*]
But instead of calling g.__next__(), use next(g).
[*] There are ...
Disable a method in a ViewSet, django-rest-framework
...ethods but I did not able to find out how to disable the PATCH method specially if you are using routers.
– Muneeb Ahmad
Mar 31 '15 at 14:56
3
...
Efficiently updating database using SQLAlchemy ORM
...ngs in mind when using the ORM and plain SQL in the same transaction. Basically, from one side, ORM data modifications will only hit the database when you flush the changes from your session. From the other side, SQL data manipulation statements don't affect the objects that are in your session.
So...
How to crop an image in OpenCV using Python
...copy region of interest
If we consider (0,0) as top left corner of image called im with left-to-right as x direction and top-to-bottom as y direction. and we have (x1,y1) as the top-left vertex and (x2,y2) as the bottom-right vertex of a rectangle region within that image, then:
roi = im[y1:y2, x1...
How to find out what type of a Mat object is with Mat::type() in OpenCV
...";
r += (chans+'0');
return r;
}
If M is a var of type Mat you can call it like so:
string ty = type2str( M.type() );
printf("Matrix: %s %dx%d \n", ty.c_str(), M.cols, M.rows );
Will output data such as:
Matrix: 8UC3 640x480
Matrix: 64FC1 3x2
Its worth noting that there are also Matr...
Is there a benefit to defining a class inside another class in Python?
What I'm talking about here are nested classes. Essentially, I have two classes that I'm modeling. A DownloadManager class and a DownloadThread class. The obvious OOP concept here is composition. However, composition doesn't necessarily mean nesting, right?
...