大约有 40,000 项符合查询结果（耗时：0.0590秒） [XML]
C dynamically growing array
...ynamic array implementations work by starting off with an array of some (small) default size, then whenever you run out of space when adding a new element, double the size of the array. As you can see in the example below, it's not very difficult at all: (I've omitted safety checks for brevity)
type...
When to use symbols instead of strings in Ruby?
...iers. For Ruby < 2.2 only use symbols when they aren't generated dynamically, to avoid memory leaks.
Full answer
The only reason not to use them for identifiers that are generated dynamically is because of memory concerns.
This question is very common because many programming languages don't h...
What is the meaning of “… …” token? i.e. double ellipsis operator on parameter pack
...s paired with a case of a regular single ellipsis.
template<typename _Res, typename... _ArgTypes>
struct _Weak_result_type_impl<_Res(_ArgTypes...)>
{ typedef _Res result_type; };
template<typename _Res, typename... _ArgTypes>
struct _Weak_result_type_impl<_Res(...
How to filter a dictionary according to an arbitrary condition function?
...
And here is a good explanation why the function call dict() is slower than the constructor/literal syntax {} doughellmann.com/2012/11/…
– dorvak
Jul 10 '13 at 9:37
...
Adding external library into Qt Creator project
... this is like this:
LIBS += -L/path/to -lpsapi
This way it will work on all platforms supported by Qt. The idea is that you have to separate the directory from the library name (without the extension and without any 'lib' prefix). Of course, if you are including a Windows specific lib, this reall...
Python debugging tips [closed]
... same effect in the running code
ipdb is a version of pdb for IPython. It allows the use of pdb with all the IPython features including tab completion.
It is also possible to set pdb to automatically run on an uncaught exception.
Pydb was written to be an enhanced version of Pdb. Benefits?
...
PDO Prepared Inserts multiple rows in single query
... table (fielda, fieldb, ... ) values (?,?...), (?,?...)....
That is basically how we want the insert statement to look like.
Now, the code:
function placeholders($text, $count=0, $separator=","){
$result = array();
if($count > 0){
for($x=0; $x<$count; $x++){
$re...
getenv() vs. $_ENV in PHP
What is the difference between getenv() and $_ENV ?
6 Answers
6
...
What breaking changes are introduced in C++11?
...nity, whereas C++0x always rounds the result toward 0.
(admittedly not really a compatibility problem for most people).
Valid C++ 2003 code that uses the keyword auto as a storage class specifier may be invalid in C++0x.
Narrowing conversions cause incompatibilities with C++03. For ex...
Regex not operator
...: lookahead) this doesn't (hence: negative) match this. But it doesn't actually consume the characters it matches (hence: zero-width).
There are actually 4 combinations of lookarounds with 2 axes:
lookbehind / lookahead : specifies if the characters before or after the point are considered
positi...