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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...
How do you detect/avoid Memory leaks in your (Unmanaged) code? [closed]
...e quick summary of those articles. First, include these headers:
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
Then you need to call this when your program exits:
_CrtDumpMemoryLeaks();
Alternatively, if your program does not exit in the same place every time, ...
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');
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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...
How to prevent a background process from being stopped after closing SSH client in Linux
... between you and the process.
Create as coproc.sh:
#!/bin/bash
IFS=
run_in_coproc () {
echo "coproc[$1] -> main"
read -r; echo $REPLY
}
# dynamic-coprocess-generator. nice.
_coproc () {
local i o e n=${1//[^A-Za-z0-9_]}; shift
exec {i}<> <(:) {o}<> >(:) {e}&...
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
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...
in_array() and multidimensional array
I use in_array() to check whether a value exists in an array like below,
22 Answers
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How to map and remove nil values in Ruby
...
Ruby 2.7+
There is now!
Ruby 2.7 is introducing filter_map for this exact purpose. It's idiomatic and performant, and I'd expect it to become the norm very soon.
For example:
numbers = [1, 2, 5, 8, 10, 13]
enum.filter_map { |i| i * 2 if i.even? }
# => [4, 16, 20]
In your ...
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...
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);
...