大约有 45,000 项符合查询结果（耗时：0.0603秒） [XML]
How can I negate the return-value of a process?
...at negates the value a process returns. It should map 0 to some value != 0 and any value != 0 to 0, i.e. the following command should return "yes, nonexistingpath doesn't exist":
...
Programmatically creating Markdown tables in R with KnitR
I am just starting to learn about KnitR and the use of Markdown in generating R documents and reports. This looks to be perfect for a lot of the day to day reporting that I have to do with my job. However, one thing that I'm not seeing is an easy way to print data frames and tables using Markdown fo...
CentOS+Nginx+PHP+MySQL详细配置(图解) - PHP - 清泛IT论坛，有思想、有深度
本帖最后由 zqp2013 于 2015-4-26 14:29 编辑
一、安装MySQL
        目前web服务器已经很少有跑静态页面的，如果要跑动态网站那当然就离不开数据库，虽然在以前文章中有写MySQL是怎么安装的，但是感觉好久没...
How do I know if a generator is empty from the start?
...
Oh, and for reference, I tried implementing my own "fancy decorator" suggestion. HARD. Apparently copy.deepcopy doesn't work on generators.
– David Berger
Mar 19 '09 at 19:50
...
What is the difference between GitHub and gist?
What is the purpose of gist and how is it different from regular code sharing/maintaining using GitHub?
8 Answers
...
Why does integer division in C# return an integer and not a float?
Does anyone know why integer division in C# returns an integer and not a float?
What is the idea behind it? (Is it only a legacy of C/C++?)
...
std::unique_lock or std::lock_guard?
...
The difference is that you can lock and unlock a std::unique_lock. std::lock_guard will be locked only once on construction and unlocked on destruction.
So for use case B you definitely need a std::unique_lock for the condition variable. In case A it depends ...
Can modules have properties the same way that objects can?
... Did anybody else try this? When I put this code in one file x.py and import it from another, then calling x.y results in AttributeError: 'NoneType' object has no attribute 'c', since _M somehow has value None...
– Stephan202
May 19 '09 at 1:35
...
Why is “if not someobj:” better than “if someobj == None:” in Python?
... the object has a __nonzero__ special method (as do numeric built-ins, int and float), it calls this method. It must either return a bool value which is then directly used, or an int value that is considered False if equal to zero.
Otherwise, if the object has a __len__ special method (as do contain...
Difference between . and : in Lua
I am confused about the difference between function calls via . and via :
3 Answers
...