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MySQL Query GROUP BY day / month / year
...may be more efficient than DATE_FORMAT(). (I don't have a MySQL for proper testing, though.)
– Andriy M
Mar 26 '13 at 12:23
...
Java LinkedHashMap get first or last entry
...import java.util.Map;
import java.util.Map.Entry;
public class PerformanceTest {
private static long startTime;
private static long endTime;
private static LinkedHashMap<Integer, String> linkedmap;
public static void main(String[] args) {
linkedmap = new LinkedHashMa...
Difference between & and && in Java? [duplicate]
...
'&' performs both tests, while '&&' only performs the 2nd test if the first is also true. This is known as shortcircuiting and may be considered as an optimization. This is especially useful in guarding against nullness(NullPointerExce...
How do I check that multiple keys are in a dict in a single pass?
... It's a good solution thanks to short-circuiting, especially if the test fails more often than not; unless you can create the set of keys of interest just once and check it many times, in which case set is superior. As usual... measure it!-)
– Alex Martelli
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When should you use 'friend' in C++?
...
At work we use friends for testing code, extensively. It means we can provide proper encapsulation and information hiding for the main application code. But also we can have separate test code that uses friends to inspect internal state and data for te...
Regular expression that matches valid IPv6 addresses
...v4-Embedded IPv6 Address)
)
I posted a script on GitHub which tests the regular expression: https://gist.github.com/syzdek/6086792
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FFmpeg: How to split video efficiently?
...uiet -y -i input.ts -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 -sn test1.mkv
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:30:00 -t 01:00:00 -sn test2.mkv
echo "One command"
time ffmpeg -v quiet -y -i input.ts -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 \
-sn...
What's the difference between “Write-Host”, “Write-Output”, or “[console]::WriteLine”?
...he scenes.
Run this demonstration code and examine the result.
function Test-Output {
Write-Output "Hello World"
}
function Test-Output2 {
Write-Host "Hello World" -foreground Green
}
function Receive-Output {
process { Write-Host $_ -foreground Yellow }
}
#Output piped to another ...
&& (AND) and || (OR) in IF statements
...ill not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other way around
if (str == null || str.isEmpty()) {
complainAboutUnusa...
How to validate date with format “mm/dd/yyyy” in JavaScript?
...ut string is a valid date formatted as "mm/dd/yyyy"
function isValidDate(dateString)
{
// First check for the pattern
if(!/^\d{1,2}\/\d{1,2}\/\d{4}$/.test(dateString))
return false;
// Parse the date parts to integers
var parts = dateString.split("/");
var day = parseInt...