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What is the best way to implement nested dictionaries?
...getting this behavior, here's how to shoot yourself in the foot:
Implement __missing__ on a dict subclass to set and return a new instance.
This approach has been available (and documented) since Python 2.5, and (particularly valuable to me) it pretty prints just like a normal dict, instead of the u...
What does the “yield” keyword do?
...ou create the method of the node object that will return the generator
def _get_child_candidates(self, distance, min_dist, max_dist):
# Here is the code that will be called each time you use the generator object:
# If there is still a child of the node object on its left
# AND if the d...
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...
Count number of records returned by group by
...rGroup,
COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4
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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...
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...
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
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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 ...
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...
Reference — What does this symbol mean in PHP?
...
_ Alias for gettext()
The underscore character '_' as in _() is an alias to the gettext() function.
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