大约有 19,000 项符合查询结果（耗时：0.0578秒） [XML]
How do you calculate the average of a set of circular data? [closed]
...e, A, from a set of angle measurements
a[i] 0<=i
sum_i_from_1_to_N sin(a[i])
a = arctangent ---------------------------
sum_i_from_1_to_N cos(a[i])
The method given by starblue is computationally equivalent, but his reasons are clearer and probably program...
How to import the class within the same directory or sub directory?
...
Python 2
Make an empty file called __init__.py in the same directory as the files. That will signify to Python that it's "ok to import from this directory".
Then just do...
from user import User
from dir import Dir
The same holds true if the files are in a...
Getting list of parameter names inside python function [duplicate]
....
>>> func = lambda x, y: (x, y)
>>>
>>> func.__code__.co_argcount
2
>>> func.__code__.co_varnames
('x', 'y')
>>>
>>> def func2(x,y=3):
... print(func2.__code__.co_varnames)
... pass # Other things
...
>>> func2(3,3)
('x', 'y')
>...
How do I filter query objects by date range in Django?
...
Use
Sample.objects.filter(date__range=["2011-01-01", "2011-01-31"])
Or if you are just trying to filter month wise:
Sample.objects.filter(date__year='2011',
date__month='01')
Edit
As Bernhard Vallant said, if you want a query...
Why prefer two's complement over sign-and-magnitude for signed numbers?
...icle on two's complement for the full answer: en.wikipedia.org/wiki/Two%27s_complement. The short answer is the MSB 1 indicates -8, and the remaining three 1s indicate 4, 2, and 1, respectively, so -8+4+2+1 = -1.
– Welbog
Aug 23 '16 at 13:33
...
How does deriving work in Haskell?
... Haskell Wiki:
In this example we use the following Haskell code
$(gen_render ''Body)
to produce the following instance:
instance TH_Render Body where
render (NormalB exp) = build 'normalB exp
render (GuardedB guards) = build 'guardedB guards
The function gen_render above is d...
List all indexes on ElasticSearch server?
...ise list of all indices in your cluster, call
curl http://localhost:9200/_aliases
this will give you a list of indices and their aliases.
If you want it pretty-printed, add pretty=true:
curl http://localhost:9200/_aliases?pretty=true
The result will look something like this, if your indices ...
Instance attribute attribute_name defined outside __init__
.... We expect to find all the attributes an instance may have by reading its __init__ method.
You may still want to split initialization into other methods though. In such case, you can simply assign attributes to None (with a bit of documentation) in the __init__ then call the sub-initialization met...
How can I recover the return value of a function passed to multiprocessing.Process?
... For example like this:
import multiprocessing
def worker(procnum, return_dict):
'''worker function'''
print str(procnum) + ' represent!'
return_dict[procnum] = procnum
if __name__ == '__main__':
manager = multiprocessing.Manager()
return_dict = manager.dict()
jobs = []
...
Django 1.7 - makemigrations not detecting changes
... out) listed in the documentation:
python manage.py makemigrations your_app_label
The documentation does not make it obvious that you need to add the app label to the command, as the first thing it tells you to do is python manage.py makemigrations which will fail. The initial migration is don...