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How to use the PI constant in C++
...acro
* definitions for common math constants. These are placed under an #ifdef
* since these commonly-defined names are not part of the C/C++ standards.
*/
However:
on newer platforms (at least on my 64 bit Ubuntu 14.04) I do not need to define the _USE_MATH_DEFINES
On (recent) Linux platfo...
Getting Django admin url for an object
... just shows how to properly add the admin app to your app, which solved a different problem that the author had. The real answer to the actual question is below - from markmuetz
– Declan Shanaghy
Aug 19 '11 at 18:18
...
How to replace plain URLs with links?
...s, and there are a few worth using despite some downsides:
Soapbox's linkify has seen some serious effort put into it, and a major refactor in June 2015 removed the jQuery dependency. It still has issues with IDNs.
AnchorMe is a newcomer that claims to be faster and leaner. Some IDN issues as well...
Adding information to an exception?
... %s' % arg1)
IOError: Stuff happens at arg1
Update 1
Here's a slight modification that preserves the original traceback:
...
def bar(arg1):
try:
foo()
except Exception as e:
import sys
raise type(e), type(e)(e.message +
' happens at ...
Calculate difference in keys contained in two Python dictionaries
...e I have two Python dictionaries - dictA and dictB . I need to find out if there are any keys which are present in dictB but not in dictA . What is the fastest way to go about it?
...
Can “list_display” in a Django ModelAdmin display attributes of ForeignKey fields?
...showing each person would make a SQL query.
To avoid this, you need to modify get_queryset method in PersonAdmin, for example:
def get_queryset(self, request):
return super(PersonAdmin,self).get_queryset(request).select_related('book')
Before: 73 queries in 36.02ms (67 duplicated queries ...
When I catch an exception, how do I get the type, file, and line number?
...ould be careful about unpacking sys.exc_info() into local variables, since if you get an exception in the except handler, the local vars could get kept in a circular reference and not GC'd. Best practice is to always just use slices off of sys.exc_info() instead. Or use other modules like tracebac...
Random Gaussian Variables
...ution. A simple implementation:
Random rand = new Random(); //reuse this if you are generating many
double u1 = 1.0-rand.NextDouble(); //uniform(0,1] random doubles
double u2 = 1.0-rand.NextDouble();
double randStdNormal = Math.Sqrt(-2.0 * Math.Log(u1)) *
Math.Sin(2.0 * Math.PI * u2);...
Getting MAC Address
...module can be used and the only method under Linux I could find was to run ifconfig and run a regex across its output. I don't like using a package that only works on one OS, and parsing the output of another program doesn't seem very elegant not to mention error prone.
...
Why does sys.exit() not exit when called inside a thread in Python?
...
What if I did want to exit the program
from the thread?
Apart from the method Deestan described you can call os._exit (notice the underscore). Before using it make sure that you understand that it does no cleanups (like callin...