大约有 13,700 项符合查询结果(耗时:0.0294秒) [XML]
Assigning a variable NaN in python without numpy
...e 1, in <module>
File "C:\Python35\lib\fractions.py", line 146, in __new__
numerator)
ValueError: Invalid literal for Fraction: 'nan'
>>>
>>> Fraction(float('nan'))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python35\...
How can I escape square brackets in a LIKE clause?
...derscore from a query, so I ended up with this:
WHERE b.[name] not like '\_%' escape '\' -- use \ as the escape character
share
|
improve this answer
|
follow
...
Django rest framework nested self-referential objects
...('parentCategory', 'name', 'description', 'subcategories')
def get_related_field(self, model_field):
# Handles initializing the `subcategories` field
return CategorySerializer()
Actually, as you've noted the above isn't quite right.
This is a bit of a hack, but y...
python exception message capturing
...is no longer supported in python 3. Use the following instead.
try:
do_something()
except BaseException as e:
logger.error('Failed to do something: ' + str(e))
share
|
improve this answer
...
django - why is the request.POST object immutable?
...QueryDict class, which implements a full set of mutation methods including __setitem__, __delitem__, pop and clear. It implements immutability by checking a flag when you call one of the mutation methods. And when you call the copy method you get another QueryDict instance with the mutable flag turn...
What's the dSYM and how to use it? (iOS SDK)
... 0x000000018f3c9380 closure #1 in closure #1 in closure #1 in _assertionFailure+ 217984 (_:_:file:line:flags:) + 452
1 libswiftCore.dylib 0x000000018f3c9380 closure #1 in closure #1 in closure #1 in _assertionFailure+ 217984 (_:_:file:line:flags:) + 452
2 libswiftCore.d...
django change default runserver port
...ith the following:
#!/bin/bash
exec ./manage.py runserver 0.0.0.0:<your_port>
save it as runserver in the same dir as manage.py
chmod +x runserver
and run it as
./runserver
share
|
imp...
What is the volatile keyword useful for?
... volatile:
public class Singleton {
private static volatile Singleton _instance; // volatile variable
public static Singleton getInstance() {
if (_instance == null) {
synchronized (Singleton.class) {
if (_instance == null)
_instance = ...
Best algorithm for detecting cycles in a directed graph [closed]
...e following Wikipedia article:
http://en.wikipedia.org/wiki/Topological_sorting
has the pseudo-code for one algorithm, and a brief description of another from Tarjan. Both have O(|V| + |E|) time complexity.
share
...
How to calculate the bounding box for a given lat/lng location?
...return 180.0*radians/math.pi
# Semi-axes of WGS-84 geoidal reference
WGS84_a = 6378137.0 # Major semiaxis [m]
WGS84_b = 6356752.3 # Minor semiaxis [m]
# Earth radius at a given latitude, according to the WGS-84 ellipsoid [m]
def WGS84EarthRadius(lat):
# http://en.wikipedia.org/wiki/Earth_rad...