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How do I perform the SQL Join equivalent in MongoDB?
...rect. The new $lookup operator added to the aggregation pipeline is essentially identical to a left outer join:
https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup
From the docs:
{
$lookup:
{
from: <collection to join>,
localField: <...
How to explicitly discard an out argument?
...dd the line _ = {a value}; after the function call without any compilation errors.
– Bip901
Aug 5 '19 at 10:39
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Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive
...framework 4.0 and convert this into application in IIS then its shows this error
7 Answers
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Scroll Automatically to the Bottom of the Page
... list of questions. When I click on the first question, it should automatically take me to the bottom of the page.
23 Answ...
Looping over arrays, printing both index and value
...., not splitting them on whitespace. If foo=(x 'y z'), then f "${foo[@]}" calls f with two arguments, x and 'y z'. Metadata queries like "${!foo[@]}" and "${#foo[@]}" similarly act on foo as an array.
– BallpointBen
Sep 5 '18 at 1:23
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What's the most elegant way to cap a number to a segment? [closed]
...n, this is definitely my preferred answer: maxes of mins are confusing and error prone.
– Don Hatch
Jul 13 '16 at 22:21
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Why prefer two's complement over sign-and-magnitude for signed numbers?
...o add them.
Two's complement addition is very simple. You add numbers normally and any carry bit at the end is discarded. So they're added as follows:
0010
+ 1111
=10001
= 0001 (discard the carry)
0001 is 1, which is the expected result of "2+(-1)".
But in your "intuitive" method, adding is m...
Is it safe to get values from a java.util.HashMap from multiple threads (no modification)?
...ting thread makes the reference to the map visible to other threads.
Basically, the only possible race here is between the construction of the HashMap and any reading threads that may access it before it is fully constructed. Most of the discussion is about what happens to the state of the map obje...
Status bar and navigation bar appear over my view's bounds in iOS 7
... Also, unless you are building for only iOS7, the above code will throw an error - topLayoutGuide is iOS7 only.
– memmons
Oct 10 '13 at 17:11
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How can I extract a good quality JPEG image from a video file with ffmpeg?
...r ffprobe console output can tell you if your input is MJPEG:
$ ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=nw=1 input.avi
codec_name=mjpeg
Then you can extract the frames using the mjpeg2jpeg bitstream filter:
$ ffmpeg -i input.avi -codec:v copy -bsf:v mjpeg2jp...