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What is meant by immutable?
... without worrying that someone else is going to change its contents. Especially when dealing with concurrency, there are no locking issues with objects that never change
e.g.
class Foo
{
private final String myvar;
public Foo(final String initialValue)
{
this.myvar = initi...
Rails 3: Get Random Record
...; rand(Thing.count))
# Rails 3
Thing.offset(rand(Thing.count)).first
Actually, in Rails 3 all examples will work. But using order RANDOM is quite slow for big tables but more sql-style
UPD. You can use the following trick on an indexed column (PostgreSQL syntax):
select *
from my_table
where i...
What are the differences between vector and list data types in R?
...
Technically lists are vectors, although very few would use that term. "list" is one of several modes, with others being "logical", "character", "numeric", "integer". What you are calling vectors are "atomic vectors" in strict R parl...
What is the difference between JOIN and JOIN FETCH when using JPA and Hibernate
...
In this two queries, you are using JOIN to query all employees that have at least one department associated.
But, the difference is: in the first query you are returning only the Employes for the Hibernate. In the second query, you are returning the Employes and all Depart...
What is the exact problem with multiple inheritance?
I can see people asking all the time whether multiple inheritance should be included into the next version of C# or Java. C++ folks, who are fortunate enough to have this ability, say that this is like giving someone a rope to eventually hang themselves.
...
How to get started with developing Internet Explorer extensions?
...er the BHO (needs registry access).
Start by creating a class library.
I called mine InternetExplorerExtension.
Add these references to the project:
Interop.SHDocVw: COM tab / search for "Microsoft Internet Controls"
Microsoft.mshtml: Assemblies tab / search for "Microsoft.mshtml"
Note: Someho...
Add and remove multiple classes in jQuery
...eClass() only and no need to write any class name in removeClass to remove all the added classes and add any class by choice. Yes its working...!
– Raman
Aug 25 '11 at 6:49
3
...
jQuery removing '-' character from string
...in some other variable not part of the DOM, then you would likely want to call the .replace() function against that variable before you insert it into the DOM.
Like this:
var someVariable = "-123456";
$mylabel.text( someVariable.replace('-', '') );
or a more verbose version:
var someVariable = ...
How do I remove a single breakpoint with GDB?
...
You can list breakpoints with:
info break
This will list all breakpoints. Then a breakpoint can be deleted by its corresponding number:
del 3
For example:
(gdb) info b
Num Type Disp Enb Address What
3 breakpoint keep y 0x004018c3 in timeCorrect a...
设置用户默认权限 Umask命令详解 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...22 = 644
注：权限计算实际上是二进制位的与操作，参考All About the umask and Permissions。
操作bar.tar
shell> tar xf bar.tar
这次有点不同，我们要运行两次tar命令。
第一次：以root身份运行tar命令，然后查看目录和文件的权限，分别...