大约有 48,000 项符合查询结果（耗时：0.0804秒） [XML]
What's the difference between using CGFloat and float?
I tend to use CGFloat all over the place, but I wonder if I get a senseless "performance hit" with this. CGFloat seems to be something "heavier" than float, right? At which points should I use CGFloat, and what makes really the difference?
...
Do I need to explicitly call the base virtual destructor?
...the destructor again as virtual on the inheriting class, but do I need to call the base destructor?
7 Answers
...
Is module __file__ attribute absolute or relative?
...a file. The __file__ attribute is not present for C modules that are statically linked into the interpreter; for extension modules loaded dynamically from a shared library, it is the pathname of the shared library file.
From the mailing list thread linked by @kindall in a comment to the question:
...
Find which version of package is installed with pip
..., is it possible to figure out which version of a package is currently installed?
15 Answers
...
Python function attributes - uses and abuses [closed]
...
I typically use function attributes as storage for annotations. Suppose I want to write, in the style of C# (indicating that a certain method should be part of the web service interface)
class Foo(WebService):
@webmethod
de...
Adding information to an exception?
...essage + ' happens at %s' % arg1)
bar('arg1')
Traceback (most recent call last):
File "test.py", line 13, in <module>
bar('arg1')
File "test.py", line 11, in bar
raise type(e)(e.message + ' happens at %s' % arg1)
IOError: Stuff happens at arg1
Update 1
Here's a slight modif...
What is the instanceof operator in JavaScript?
...ce p inherits from Person.prototype.
Per the OP's request
I've added a small example with some sample code and an explanation.
When you declare a variable you give it a specific type.
For instance:
int i;
float f;
Customer c;
The above show you some variables, namely i, f, and c. The type...
How to validate an email address in JavaScript
...b"@gmail.com, _@gmail.com, 1@gmail.com , 1_example@something.gmail.com are all valid, but Gmail will never allow any of these email addresses. You should do this by accepting the email address and sending an email message to that email address, with a code/link the user must visit to confirm validit...
Shards and replicas in Elasticsearch
...e need to create an index.
When you create an index (an index is automatically created when you index the first document as well) you can define how many shards it will be composed of. If you don't specify a number it will have the default number of shards: 5 primaries. What does it mean?
It mean...
How do I filter query objects by date range in Django?
...year='2011',
date__month='01')
Edit
As Bernhard Vallant said, if you want a queryset which excludes the specified range ends you should consider his solution, which utilizes gt/lt (greater-than/less-than).
...