大约有 40,000 项符合查询结果（耗时：0.0439秒） [XML]
Java 8: performance of Streams vs Collections
...fects on your results. So, I increased your task 10 times
int max = 10_000_000;
and ran your benchmark. My results:
Collections: Elapsed time: 8592999350 ns (8.592999 seconds)
Streams: Elapsed time: 2068208058 ns (2.068208 seconds)
Parallel streams: Elapsed time: 7186967071 ns (7...
PostgreSQL Crosstab Query
...m is also limited to exactly three columns in the provided input query: row_name, category, value. There is no room for extra columns like in the 2-parameter alternative below.
Safe form
crosstab(text, text) with 2 input parameters:
SELECT *
FROM crosstab(
'SELECT section, status, ct
FR...
What is the performance cost of having a virtual method in a C++ class?
... be non-virtual is an abominable policy.
– underscore_d
May 20 '17 at 19:34
add a comment
...
Pagination in a REST web application
... Range header also works to declare an order:
Range: products-by-date=2009_03_27-
to get all products newer than that date or
Range: products-by-date=0-2009_11_30
to get all products older than that date. '0' is probably not best solution, but RFC seems to want something for range start. There...
Java: PrintStream to String?
...= new ByteArrayOutputStream();
final String utf8 = StandardCharsets.UTF_8.name();
try (PrintStream ps = new PrintStream(baos, true, utf8)) {
yourFunction(object, ps);
}
String data = baos.toString(utf8);
...
in_array() and multidimensional array
I use in_array() to check whether a value exists in an array like below,
22 Answers
...
Unexpected results when working with very big integers on interpreted languages
...ger types. All numbers are floating points.
– toasted_flakes
Aug 4 '13 at 22:27
8
@grasGendarme T...
Initializing a static std::map in C++
...namespace std;
using namespace boost::assign;
map<int, char> m = map_list_of (1, 'a') (3, 'b') (5, 'c') (7, 'd');
share
|
improve this answer
|
follow
...
Build tree array from flat array in javascript
...ibrary. It's, as far as I can tell, the fastest solution.
function list_to_tree(list) {
var map = {}, node, roots = [], i;
for (i = 0; i < list.length; i += 1) {
map[list[i].id] = i; // initialize the map
list[i].children = []; // initialize the children
}
for (i = 0; i ...
How to get the Full file path from URI
...ISyntaxException {
final boolean needToCheckUri = Build.VERSION.SDK_INT >= 19;
String selection = null;
String[] selectionArgs = null;
// Uri is different in versions after KITKAT (Android 4.4), we need to
// deal with different Uris.
if (needToChec...