大约有 40,000 项符合查询结果（耗时：0.0379秒） [XML]
Proper use of beginBackgroundTaskWithExpirationHandler
...ed.
Mine tend look something like this:
- (void) doUpdate
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self beginBackgroundUpdateTask];
NSURLResponse * response = nil;
NSError * error = nil;
NSData * responseData = [NSU...
Getting a list of all subdirectories in the current directory
...
Do not use os.walk('.').next()[1] or os.walk('.').__next__()[1] directly. Instead, use the built-in function next(), which is available both in Python 2 (see doc) and Python 3 (see doc). For example: next(os.walk('.'))[1].
– Lucio Paiva
...
Is it possible to make abstract classes in Python?
...
# Python 2
from abc import ABCMeta, abstractmethod
class Abstract:
__metaclass__ = ABCMeta
@abstractmethod
def foo(self):
pass
Whichever way you use, you won't be able to instantiate an abstract class that has abstract methods, but will be able to instantiate a subclass th...
How do I move to end of line in Vim?
...mode (Append). To jump the last non-blank character, you can press g then _ keys.
The opposite of A is I (Insert mode at beginning of line), as an aside. Pressing just the ^ will place your cursor at the first non-white-space character of the line.
...
Entity Framework rollback and remove bad migration
...g migrations that have been applied to the target database.
201508242303096_Bad_Migration
201508211842590_The_Migration_applied_before_it
201508211440252_And_another
This list shows the most recent applied migrations first. Pick the migration that occurs in the list after the one you want to downgr...
Python ElementTree module: How to ignore the namespace of XML files to locate matching element when
...s ET
# instead of ET.fromstring(xml)
it = ET.iterparse(StringIO(xml))
for _, el in it:
prefix, has_namespace, postfix = el.tag.partition('}')
if has_namespace:
el.tag = postfix # strip all namespaces
root = it.root
This is based on the discussion here:
http://bugs.python.org/issu...
How to calculate moving average using NumPy?
... an off-by-one wrong indexing spotted by Bean in the code. EDIT
def moving_average(a, n=3) :
ret = np.cumsum(a, dtype=float)
ret[n:] = ret[n:] - ret[:-n]
return ret[n - 1:] / n
>>> a = np.arange(20)
>>> moving_average(a)
array([ 1., 2., 3., 4., 5., 6., 7....
How to track down a “double free or corruption” error
...
If you're using glibc, you can set the MALLOC_CHECK_ environment variable to 2, this will cause glibc to use an error tolerant version of malloc, which will cause your program to abort at the point where the double free is done.
You can set this from gdb by using the s...
What is the _references.js used for?
What is the _references.js file used for in a new ASP.NET MVC 4 project?
2 Answers
2
...
What is the meaning of single and double underscore before an object name?
...owever, nothing special is done with the name itself.
To quote PEP-8:
_single_leading_underscore: weak "internal use" indicator. E.g. from M import * does not import objects whose name starts with an underscore.
Double Underscore (Name Mangling)
From the Python docs:
Any identifier of th...