大约有 47,000 项符合查询结果(耗时:0.0553秒) [XML]

https://stackoverflow.com/ques... 

In Python how should I test if a variable is None, True or False

...il" # execution continues from here, regardless of exception or not And now you can have a much richer type of notification from the simulate method as to what exactly went wrong, in case you find error/no-error not to be informative enough. ...
https://stackoverflow.com/ques... 

CHECK constraint in MySQL is not working

... @Jérôme I know, I have some (more recent) answers that include improvements in this area (there had been other ways to workaround this issue, both in MariaDB and MySQL, before MariaDB properly implemented CHECK constraints). What I'm no...
https://stackoverflow.com/ques... 

.NET console application as Windows service

...below Build the project and run "InstallUtil.exe c:\path\to\MyService.exe" Now you should see MyService on the service list (run services.msc) *InstallUtil.exe can be usually found here: C:\windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.ex‌​e Program.cs using System; using System.IO;...
https://stackoverflow.com/ques... 

How can I convert a DateTime to the number of seconds since 1970?

...e, there's a really convenient feature: long unixSeconds = DateTimeOffset.Now.ToUnixTimeSeconds(); share | improve this answer | follow | ...
https://stackoverflow.com/ques... 

What is the difference between save and export in Docker?

...r a couple of days and I already made some images (which was really fun!). Now I want to persist my work and came to the save and export commands, but I don't fully understand them. ...
https://stackoverflow.com/ques... 

class

... = 'foo' # new object, new singleton class a.inspect # => "foo" Now, to answer the question: class << self opens up self's singleton class, so that methods can be redefined for the current self object (which inside a class or module body is the class or module itself). Usually, this...
https://stackoverflow.com/ques... 

#pragma once vs include guards? [duplicate]

I'm working on a codebase that is known to only run on windows and be compiled under Visual Studio (it integrates tightly with excel so it's not going anywhere). I'm wondering if I should go with the traditional include guards or use #pragma once for our code. I would think letting the compiler de...
https://stackoverflow.com/ques... 

what exactly is device pixel ratio?

this is mentioned every article about mobile web, but nowhere I can found an explanation of what exactly does this attribute measure. Can anyone please elaborate what does queries like this check? ...
https://stackoverflow.com/ques... 

Get an object properties list in Objective-C

...ion, which is mainly taken from an Apple code sample (can't remember right now the exact source): static const char *getPropertyType(objc_property_t property) { const char *attributes = property_getAttributes(property); char buffer[1 + strlen(attributes)]; strcpy(buffer, attributes); ...
https://stackoverflow.com/ques... 

Why does the indexing start with zero in 'C'?

...out the above reasons While Dijkstra's article (previously referenced in a now-deleted answer) makes sense from a mathematical perspective, it isn't as relevant when it comes to programming. The decision taken by the language specification & compiler-designers is based on the decision made by c...