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How to dynamically load a Python class
Given a string of a Python class, e.g. my_package.my_module.MyClass , what is the best possible way to load it?
10 Answers...
Why is Python 3.x's super() magic?
...lf):
return super(Foo, self).baz() + 42
Spam = Foo
Foo = something_else()
Spam().baz() # liable to blow up
The same applies to using class decorators where the decorator returns a new object, which rebinds the class name:
@class_decorator_returning_new_class
class Foo(Bar):
def baz...
Are nested try/except blocks in python a good programming practice?
...EAFP.
Personally, I prefer to avoid nesting when it's not necessary:
def __getattribute__(self, item):
try:
return object.__getattribute__(item)
except AttributeError:
pass # fallback to dict
try:
return self.dict[item]
except KeyError:
raise Attrib...
BSS段、数据段、代码段、堆与栈 剖析 - C/C++ - 清泛网 - 专注C/C++及内核技术
...下其各自的.asm，发现在程序1.asm 中ar 的定义如下：
_BSS SEGMENT
?ar@@3PAHA DD 0493e0H DUP (?) ; ar
_BSS ENDS
而在程序2.asm 中，ar 被定义为：
_DATASEGMENT
?ar@@3PAHA DD 01H ; ar
DD 02H
DD 03H
ORG $+1199988
_DATAENDS
区别很明显，一个位于.bss 段...
MIN and MAX in C
...afety bonus too) in a GCC statement expression:
#define max(a,b) \
({ __typeof__ (a) _a = (a); \
__typeof__ (b) _b = (b); \
_a > _b ? _a : _b; })
Everyone says "oh I know about double evaluation, it's no problem" and a few months down the road, you'll be debugging the silliest ...
Python “raise from” usage
...
The difference is that when you use from, the __cause__ attribute is set and the message states that the exception was directly caused by. If you omit the from then no __cause__ is set, but the __context__ attribute may be set as well, and the traceback then shows the co...
iOS开发调试技巧总结 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...(format,...)do{\
fprintf(stderr,"%s\n",\
[[[NSStringstringWithUTF8String:__FILE__]lastPathComponent]UTF8String],\
__LINE__,__func__);\
(NSLog)((format),##__VA_ARGS__);\
fprintf(stderr,"-------\n");\
}while(0)
@interfaceViewController
@end
@implementationViewController
-(void)viewDi...
mongodb group values by multiple fields
...tems to $push to an array.
db.books.aggregate([
{ "$group": {
"_id": {
"addr": "$addr",
"book": "$book"
},
"bookCount": { "$sum": 1 }
}},
{ "$group": {
"_id": "$_id.addr",
"books": {
"$push": {
...
Chain-calling parent initialisers in python [duplicate]
...Python 3 includes an improved super() which allows use like this:
super().__init__(args)
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How can I filter a date of a DateTimeField in Django?
...
Such lookups are implemented in django.views.generic.date_based as follows:
{'date_time_field__range': (datetime.datetime.combine(date, datetime.time.min),
datetime.datetime.combine(date, datetime.time.max))}
Because it is quite verbose there are pla...