大约有 46,000 项符合查询结果（耗时：0.0623秒） [XML]
How to create abstract properties in python abstract classes
In the following code, I create a base abstract class Base . I want all the classes that inherit from Base to provide the name property, so I made this property an @abstractmethod .
...
What is a word boundary in regex?
... be "identifier" characters (alnums and underscore), not as anything especially useful for English.
– hobbs
Aug 24 '09 at 21:02
...
How to check if std::map contains a key without doing insert?
...
Use my_map.count( key ); it can only return 0 or 1, which is essentially the Boolean result you want.
Alternately my_map.find( key ) != my_map.end() works too.
share
|
improve this answer
...
Python super() raises TypeError
...You have to design any methods that need to multiply-inherit (most notably __init__) to pass through arguments in a clean and sensible way, otherwise you'll get TypeErrors or worse debugging problems when someone tries to multiply-inherit using your class. Unless you've really designed to support MI...
delegate keyword vs. lambda notation
... If you specify an anonymous method without specifying a parameter list at all it is compatible with any delegate type returning void and without any out parameters. Armed with this knowledge, we should be able to construct two overloads to make the expressions completely unambiguous but very differ...
Better way to cast object to int
... to signify a Nullable<int>. The "as" operator works like Convert.To____(), but think TryParse() rather than Parse(): it returns null rather than throwing an exception if the conversion fails.
Of these, I would prefer (int) if the object really is just a boxed integer. Otherwise use Conver...
How to change Vagrant 'default' machine name?
...
I found the multiple options confusing, so I decided to test all of them to see exactly what they do.
I'm using VirtualBox 4.2.16-r86992 and Vagrant 1.3.3.
I created a directory called nametest and ran
vagrant init precise64 http://files.vagrantup.com/precise64.box
to generate a...
Postgresql SELECT if string contains
...
You should use 'tag_name' outside of quotes; then its interpreted as a field of the record. Concatenate using '||' with the literal percent signs:
SELECT id FROM TAG_TABLE WHERE 'aaaaaaaa' LIKE '%' || tag_name || '%';
...
Animate a custom Dialog
...ion">
<item name="android:windowEnterAnimation">@anim/spin_in</item>
<item name="android:windowExitAnimation">@android:anim/slide_out_right</item>
</style>
</resources>
The windowEnterAnimation is one of my animations and is located in res...
线程访问窗口资源的问题 - C/C++ - 清泛网 - 专注C/C++及内核技术
...并行运行的窗口）。在工作线程里调用AfxGetMainWnd（）->m_hWnd出错，也会发生发生内存访问冲突。（AfxGetMainWnd得到的是当前线程的主窗口）。
2.ASSERT((p = pMap->LookupPermanent(m_hWnd)) != NULL ||
(p = pMap->LookupTemporary(m_hWnd)) != NULL)失败;从...