大约有 31,500 项符合查询结果（耗时：0.0341秒） [XML]
Favourite performance tuning tricks [closed]
...lly jack with performance. Instead of using the OR just do two selects and union them together. You get the same results at 1000x the speed.
share
|
improve this answer
|
fol...
Pointer arithmetic for void pointer in C
...s arguments to
functions, return values from
functions, and members of unions.
So this means that printf("%s", x) has the same meaning whether x has type char* or void*, but it does not mean that you can do arithmetic on a void*.
Editor's note: This answer has been edited to reflect the final...
How to insert element into arrays at specific position?
...
array_slice() can be used to extract parts of the array, and the union array operator (+) can recombine the parts.
$res = array_slice($array, 0, 3, true) +
array("my_key" => "my_value") +
array_slice($array, 3, count($array)-3, true);
This example:
$array = array(
'zero' ...
Unpivot with column name
... VALUES, when not available, can be replaced by a subquery with SELECT ... UNION ... SELECT ... Wondering about the performance of that CROSS JOIN though...
– Cristi S.
Oct 16 '18 at 20:39
...
What is the purpose of std::make_pair vs the constructor of std::pair?
... Also note that make_pair works with unnamed types, including structs, unions, lambdas, and other doodads.
– Mooing Duck
Feb 6 '15 at 22:29
add a comment
...
R - Concatenate two dataframes?
...
If you're getting the union of more than 2 data frames, you can use Reduce(rbind, list_of_data_frames) to mash them all together!
– Yourpalal
Aug 13 '15 at 21:12
...
How can I merge properties of two JavaScript objects dynamically?
...d use object spread:
let merged = {...obj1, ...obj2};
merged is now the union of obj1 and obj2. Properties in obj2 will overwrite those in obj1.
/** There's no limit to the number of objects you can merge.
* Later properties overwrite earlier properties with the same name. */
const allRules = ...
Is Mono ready for prime time? [closed]
...e experience than using the GUI, which is a very "unorthodox" state of the union for Linux environments...
Once/During getting your stuff actually BUILT, you might see some wildernesses even for code that SHOULD be supported like:
the compiler getting borked on certain constructs
and certain mo...
How to get the top 10 values in postgresql?
...ns here>
WHERE <various conditions>
ORDER BY date DESC
LIMIT 10)
UNION ALL
(SELECT <some columns>
FROM mytable
<maybe some joins here>
WHERE <various conditions>
ORDER BY date ASC
LIMIT 10)
...
How different is Objective-C from C++? [closed]
...that can be done at compile time. For example, using a variant type(like a union) the compiler can enforce that all cases are written or handled. So you don't forget about handling the edge cases of a problem. However, all these checks come at a price when compiling. Obj-C is much faster at compilin...