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Why is there a difference in checking null against a value in VB.NET and C#?
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VB.NET and C#.NET are different languages, built by different teams who have made different assumptions about usage; in this case the semantics of a NULL comparison.
My personal preference is for the VB.NET semantics, which in essence gives NULL the semantics "I don't know...
How do I decode HTML entities in Swift?
...gt;
becomes
4 < 5 & 3 > 2
On OS X there is CFXMLCreateStringByUnescapingEntities() which does the job:
let encoded = "<strong> 4 &lt; 5 &amp; 3 &gt; 2 .</strong> Price: 12 &#x20ac;. &#64; "
let decoded = CFXMLCreateStringByUnescapingEntities(nil, enco...
What is the difference between the add and offer methods in a Queue in Java?
... to method
Collection.add(E), which can fail to
insert an element only by throwing an
exception.
share
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What do commas and spaces in multiple classes mean in CSS?
... I understand that we can apply one rule to several classes separated by comas. It's not clear to me why some classes in the example are not separated by commas.
– Roman
Jul 27 '10 at 13:53
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grepping using the “|” alternative operator
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By default, grep treats the typical special characters as normal characters unless they are escaped. So you could use the following:
grep 'gene\|exon' AT5G60410.gff
However, you can change its mode by using the following f...
Nginx与Lua - 更多技术 - 清泛网 - 专注C/C++及内核技术
...，如下资料可供参考：
ngx_openresty: an Nginx ecosystem glued by Lua
淘宝网Nginx应用、定制与开发实战
推荐看看春哥在Tech-Club上关于『由Lua粘合的Nginx生态环境』的演讲实录，有料！
安装
需要最新版的Nginx，LuaJIT，ngx_devel_kit，ngx_l...
What is the Java string pool and how is “s” different from new String(“s”)? [duplicate]
What is meant by String Pool ? And what is the difference between the following declarations:
5 Answers
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How do I specify local .gem files in my Gemfile?
...talling .gem packages, but you can specify all kinds of locations on a gem-by-gem basis by editing your Gemfile.
Specifying a :path attribute will install the gem from that path on your local machine.
gem "foreman", path: "/Users/pje/my_foreman_fork"
Alternately, specifying a :git attribute will...
How to use single storyboard uiviewcontroller for multiple subclass
...ryboard are linked up to their properties in the view controller.
It will by default initialize with the view controller that is specified in the storyboard definition.
If you are trying to gain reuse of UI elements you created in the storyboard, they still must be linked or associated to properti...
INSERT … ON DUPLICATE KEY (do nothing)
...:
simple.
cons:
too slow.
auto-increment key will CHANGE(increase by 1) if there is entry matches unique key or primary key, because it deletes the old entry then insert new one.
2. INSERT IGNORE
pros:
simple.
cons:
auto-increment key will not change if there is entry matches uni...