大约有 44,000 项符合查询结果（耗时：0.0510秒） [XML]
Most efficient way to check for DBNull and then assign to a variable?
...
Old now, but I've recently seen a number of cases where this was exactly what the profiler said to fix. Imagine evaluating large data sets, where every cell needs to make this check. Optimizing that can can reap big rewards. But ...
How to use background thread in swift?
..., after the previous code in outer block")
})
})
Pre Swift 1.2 – Known issue
As of Swift 1.1 Apple didn't support the above syntax without some modifications. Passing QOS_CLASS_BACKGROUND didn't actually work, instead use Int(QOS_CLASS_BACKGROUND.value).
For more information see Apples do...
Google Play app description formatting
I've made an Android application that is available on Google Play. Now I want to add some more formatting to my app description (eg. indent, links, lists..). But I cannot find any website where possible formatting is listed. Google Help pages cannot help me either on this subject. There exists a lot...
How do I import other TypeScript files?
...
I feel completely lost right now, no matter what I do, the compiler generates a separate .js for each .ts file and there are no "require" code in either of them... also " import moo=module("moo"); " gives an error that the name moo does not exist in the ...
Map enum in JPA with fixed values?
...
This is now possible with JPA 2.1:
@Column(name = "RIGHT")
@Enumerated(EnumType.STRING)
private Right right;
Further details:
http://java.dzone.com/articles/mapping-enums-done-right
http://www.thoughts-on-java.org/jpa-21-how-to-...
Boost.Asio的简单使用(Timer,Thread,Io_service类) - C/C++ - 清泛网 - 专注C/C++及内核技术
...()
{
using namespace std; // For time_t, time and ctime;
time_t now = time(0);
return ctime(&now);
}
int main()
{
try
{
asio::io_service io_service;
新建一个asio::ip::tcp::acceptor对象来监听新的连接.我们监听TCP端口13,IP版本为V4
...
module.exports vs exports in Node.js
... want to export a constructor function then there is something you should know about using module.exports or exports;(Remember again that module.exports will be returned when you require something, not export).
module.exports = function Something() {
console.log('bla bla');
}
Now typeof retur...
Why does struct alignment depend on whether a field type is primitive or user-defined?
...lds, clases obviously cannot do that so they will remain 8 byte aligned.
Now if we combine all that and create struct:
struct RefAndTwoInt32Wrappers
{
public int x,y;
public Int32Wrapper z;
public string s;
}
It will have 24 bytes {x,y} will have 4 bytes each and {z,s} will have 8 b...
Change R default library path using .libPaths in Rprofile.site fails to work
...getenv())) ]
The two that matter for storing and accessing packages are (now different on a Linux box):
R_LIBS_SITE /usr/local/lib/R/site-library:/usr/lib/R/site-library:/usr/lib/R/library
R_LIBS_USER /home/david/R/x86_64-pc-linux-gnu-library/3.5....
What does “hashable” mean in Python?
...
if it has hash value now what is hash value. can you give some example
– user1755071
Jan 26 '13 at 9:56
...