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Why prefer two's complement over sign-and-magnitude for signed numbers?
...o add them.
Two's complement addition is very simple. You add numbers normally and any carry bit at the end is discarded. So they're added as follows:
0010
+ 1111
=10001
= 0001 (discard the carry)
0001 is 1, which is the expected result of "2+(-1)".
But in your "intuitive" method, adding is m...
How do I check OS with a preprocessor directive?
...Unix (Linux, *BSD, Mac OS X)
See this related question on some of the pitfalls of using this check.
unix
__unix
__unix__
Mac OS X
__APPLE__
__MACH__
Both are defined; checking for either should work.
Linux
__linux__
linux Obsolete (not POSIX compliant)
__linux Obsolete (not POSIX compliant)
...
Can a decorator of an instance method access the class?
I have something roughly like the following. Basically I need to access the class of an instance method from a decorator used upon the instance method in its definition.
...
How to remove all of the data in a table using Django
...
Inside a manager:
def delete_everything(self):
Reporter.objects.all().delete()
def drop_table(self):
cursor = connection.cursor()
table_name = self.model._meta.db_table
sql = "DROP TABLE %s;" % (table_name, )
cursor.execute(sql)
...
How to add a custom loglevel to Python's logging facility
...for my application, as I don't think that debug() is sufficient. Additionally log(5, msg) isn't what I want. How can I add a custom loglevel to a Python logger?
...
Django filter queryset __in for *every* item in list
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Summary:
One option is, as suggested by jpic and sgallen in the comments, to add .filter() for each category. Each additional filter adds more joins, which should not be a problem for small set of categories.
There is the aggregation approach. This query would be shorter and...
Does Python have “private” variables in classes?
...ass variables. In Java, nothing prevents you from doing the same if you really want to - after all, you can always edit the source of the class itself to achieve the same effect. Python drops that pretence of security and encourages programmers to be responsible. In practice, this works very nicely...
Define a lambda expression that raises an Exception
...ur goal is to avoid a def, this obviously doesn't cut it. It does, however allow you to conditionally raise exceptions, e.g.:
y = lambda x: 2*x if x < 10 else raise_(Exception('foobar'))
Alternatively you can raise an exception without defining a named function. All you need is a strong stom...
Does python have an equivalent to Java Class.forName()?
...takes a fully qualified class name and returns the class, however you have all the pieces needed to build that, and you can connect them together.
One bit of advice though: don't try to program in Java style when you're in python.
If you can explain what is it that you're trying to do, maybe we ca...
get current url in twig template?
...ttributes.get('_route_params')) %}
The app global view variable contains all sorts of useful shortcuts, such as app.session and app.security.token.user, that reference the services you might use in a controller.
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