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Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
...signing by reference. But you don't use it like you would in base :
DT[3,"foo"] := newvalue # not like this
you use it like this :
DT[3,foo:=newvalue] # like this
That changed DT by reference. Say you add a new column new by reference to the data object, there is no need to do this :
DT...
Declare a block method parameter without using a typedef
...ally be preferred for more complicated cases.
– Fred Foo
Mar 30 '11 at 13:35
3
- ( void )myMethod...
Custom HTTP headers : naming conventions
... It's a matter of preference and name-spacing; concerns about "X-ClientDataFoo" being supported by any proxy or vendor without the "X" are clearly misplaced.
There's nothing special or magical about the "X-" prefix, but it helps to make it clear that it is a custom header. In fact, RFC-6648 et al h...
php发送get、post请求的几种方法 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...file_get_contents函数,以post方式获取url
<?php
$data = array ('foo' => 'bar');
//生成url-encode后的请求字符串，将数组转换为字符串
$data = http_build_query($data);
$opts = array (
<span style="white-space:pre"> </span>'http' => array (
<span style="white-space:pre"...
Type-juggling and (strict) greater/lesser-than comparisons in PHP
...$a <= $b and $b <= $a does not follow $a == $b:
var_dump(NAN <= "foo"); // bool(true)
var_dump("foo" <= NAN); // bool(true)
var_dump(NAN == "foo"); // bool(false)
PHP's <= operator is not transitive, i.e. from $a <= $b and $b <= $c does not follow $a <= $c (Example same as ...
How do servlets work? Instantiation, sessions, shared variables and multithreading
...ect thisIsThreadSafe;
thisIsNOTThreadSafe = request.getParameter("foo"); // BAD!! Shared among all requests!
thisIsThreadSafe = request.getParameter("foo"); // OK, this is thread safe.
}
}
See also:
What is the difference between JSF, Servlet and JSP?
Best option for Sessio...
How to read a (static) file from inside a Python package?
...irectory that itself is added to sys.path. E.g. with sys.path = [..., '.../foo', '.../bar.zip'], eggs go in .../foo, but packages in bar.zip can also be imported. You cant use pkg_resources to extract data from packages in bar.zip. I haven't checked if setuptools registers the necessary loader for i...
Undo scaffolding in Rails
...db:rollback
You can create scaffolding using:
rails generate scaffold MyFoo
(or similar), and you can destroy/undo it using
rails destroy scaffold MyFoo
That will delete all the files created by generate, but not any additional changes you may have made manually.
...
public friend swap member function
...unding namespace. For example, these were equivalent pre-standard:
struct foo
{
friend void bar()
{
// baz
}
};
// turned into, pre-standard:
struct foo
{
friend void bar();
};
void bar()
{
// baz
}
However, when ADL was invented this was removed. The friend fun...
How to enter quotes in a Java string?
...le name. Also, your code is needlessly complex. This would do fine: String foo = quotes + "ROM" + quotes;. No need for all those extra "".
– Duncan Jones
Mar 18 '15 at 8:55
ad...