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MongoDB: Combine data from multiple collections into one..how?
...ce076cdf52e541d9d29"),
"isbn": "978-3-16-148999-9",
"copies_sold": 1000
}
To merge both collections is just a matter of using $lookup in the following way:
db.books.aggregate([{
$lookup: {
from: "books_selling_data",
localField: "isbn",
foreignField...
Performance of FOR vs FOREACH in PHP
...decided to do a quick benchmark run...
$a = array();
for ($i = 0; $i < 10000; $i++) {
$a[] = $i;
}
$start = microtime(true);
foreach ($a as $k => $v) {
$a[$k] = $v + 1;
}
echo "Completed in ", microtime(true) - $start, " Seconds\n";
$start = microtime(true);
foreach ($a as $k => ...
Is it better to use std::memcpy() or std::copy() in terms to performance?
...nces you'd see a difference in times this extreme by chance are about 1 in 100 million (first) and 1 in 20,000 (last).
– TooTone
Mar 11 '16 at 13:24
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...
App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎...
...工作，因此不会阻塞主 UI 线程。这对于在可能需要超过 100 毫秒左右的操作期间获得良好的用户体验非常重要。阻塞主 UI 线程将使您的应用程序看起来“冻结”并变得无响应，用户不喜欢这样。
当您需要执行需要一段时间的数...
Why em instead of px?
...implest zoom method: scaling the entire page. But it means at 150% zoom, a 1000px wide page becomes 1500px wide. It's the easiest way to zoom for web & browser developers. Unfortunately, it's not very user-friendly. Which is why other browsers have text-zooming that magnifies the content only wi...
PUT vs. POST in REST
...sure whether his request made it through, it can just send it a second (or 100th) time, and it is guaranteed by the HTTP spec that this has exactly the same effect as sending once.
– Jörg W Mittag
Mar 10 '09 at 15:17
...
what exactly is device pixel ratio?
...ifferent sources for different media queries, but the support is still not 100 % since most web developers still have to support IE11 for a while more (source: caniuse).
If you need crisp images for icons, line-art, design elements that are not photos, you need to start thinking about SVG, which sc...
What is the difference between Google App Engine and Google Compute Engine?
....
The biggest difference with App Engine is that functions are priced per 100 milliseconds, while App Engine's instances shut down only after 15 minutes of inactivity. Another advantage is that Cloud Functions execute immediately, while a call to App Engine may require a new instance - and cold-sta...
How to “warm-up” Entity Framework? When does it get “cold”?
...
+100
What would be the best approach to have high availability on my Entity Framework at anytime?
You can go for a mix of pregenerated...
Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V
...lts (n => number of A's):
7 => 9
8 => 12
9 => 16
10 => 20
100 => 1391569403904
1,000 => 3268160001953743683783272702066311903448533894049486008426303248121757146615064636953144900245
174442911064952028008546304
50,000 => a very large number!
I agree with @SB that you shou...