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Check if OneToOneField is None in Django
...ately, this doesn't work all the time. In case you want to work with select_related() now or in the future -- or maybe even to be sure you also handle other sorts of magic which may happen elsewhere -- you have to extend the test as follows: if hasattr(object, 'onetoonerevrelattr') and object.onetoo...
Is it worth using Python's re.compile?
...e.py (comments are mine):
def match(pattern, string, flags=0):
return _compile(pattern, flags).match(string)
def _compile(*key):
# Does cache check at top of function
cachekey = (type(key[0]),) + key
p = _cache.get(cachekey)
if p is not None: return p
# ...
# Does act...
Can a variable number of arguments be passed to a function?
... this. The key point is that the general signature of a function is f(*list_args, **keyword_args) (not f(*list_args)).
– Eric O Lebigot
Mar 15 '13 at 3:36
...
Extracting bits with a single multiplication
...and, namely SMT-LIB 2 input:
(set-logic BV)
(declare-const mask (_ BitVec 64))
(declare-const multiplicand (_ BitVec 64))
(assert
(forall ((x (_ BitVec 64)))
(let ((y (bvmul (bvand mask x) multiplicand)))
(and
(= ((_ extract 63 63) x) ((_ extract 63 63) y))
(= ...
How do you query for “is not null” in Mongo?
...
db.collection_name.find({"filed_name":{$exists:true}});
fetch documents that contain this filed_name even it is null.
My proposition:
db.collection_name.find({"field_name":{$type:2}}) //type:2 == String
You can check on the required...
nodejs get file name from absolute path?
... extension from filename, you can use
https://nodejs.org/api/path.html#path_path_basename_path_ext
path.basename('/foo/bar/baz/asdf/quux.html', '.html');
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How can I get the current screen orientation?
...
This only provides two values ORIENTATION_PORTRAIT and ORIENTATION_LANDSCAPE. Is there a way to get all the four values from ActivityInfo? (That is LANDSCAPE_REVERSE and PORTRAIT_REVERSE as well)
– HRJ
May 4 '11 at 9:56
...
Generate a heatmap in MatPlotLib using a scatter data set
...
x = y = NP.linspace(-5, 5, 100)
X, Y = NP.meshgrid(x, y)
Z1 = ML.bivariate_normal(X, Y, 2, 2, 0, 0)
Z2 = ML.bivariate_normal(X, Y, 4, 1, 1, 1)
ZD = Z2 - Z1
x = X.ravel()
y = Y.ravel()
z = ZD.ravel()
gridsize=30
PLT.subplot(111)
# if 'bins=None', then color of each hexagon corresponds directly to i...
Getter and Setter declaration in .NET [duplicate]
...ed property. When the need arises you can expand your property to:
string _myProperty;
public string MyProperty
{
get { return _myProperty; }
set { _myProperty = value; }
}
Now you can add code that validates the value in your setter:
set
{
if (string.IsNullOrWhiteSpace(value))
...
What is the use of join() in Python threading?
... @Aviator45003: Yes, by using the timeout argument like: demon_thread.join(0.0), join() is by default blocking without regard to the daemonized attribute. But joining a demonized thread opens most likely a whole can of trouble! I'm now considering to remove the join() call in my little ...