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Grouped LIMIT in PostgreSQL: show the first N rows for each group?
... For those who works with like millions rows and seeks for really performant way to do this - poshest's answer is the way to go. Just dont forget to spice ti up with proper indexing.
– Diligent Key Presser
Jun 20 '19 at 8:46
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What is Dependency Injection and Inversion of Control in Spring Framework?
...ted from our application code to the Spring container; this phenomenon is called IoC.
Dependency Injection can be done by setter injection or constructor injection.
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Why do people write the #!/usr/bin/env python shebang on the first line of a Python script?
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If you have several versions of Python installed, /usr/bin/env will ensure the interpreter used is the first one on your environment's $PATH. The alternative would be to hardcode something like #!/usr/bin/python; that's ok, but less flexible.
In Unix, an executable f...
Show an image preview before upload
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HTML5 comes with File API spec, which allows you to create applications that let the user interact with files locally; That means you can load files and render them in the browser without actually having to upload the files. Part of the File API is the FileReader...
Can you resolve an angularjs promise before you return it?
...Nizet's Plunkr but refactored to work within the context of what was originally asked (i.e. a function call to service) and actually on site.
Inside the service...
function getSomething(id) {
// There will always be a promise so always declare it.
var deferred = $q.defer();
if (Cache[i...
Is 'float a = 3.0;' a correct statement?
...terals notation in specific scenarios.
For performance reasons:
Specifically, consider:
float foo(float x) { return x * 0.42; }
Here the compiler will emit a conversion (that you will pay at runtime) for each returned value. To avoid it you should declare:
float foo(float x) { return x * 0.42...
Is it smart to replace boost::thread and boost::mutex with c++11 equivalents?
...ried explaining the quality of boost, then gave up after some time :( ). Smaller reason why I would like to do it is that I would like to learn c++11 features, because people will start writing code in it.
So:
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Run java jar file on a server as background process
...on
[Service]
ExecStart=/usr/bin/java -jar /web/server.jar
User=user
[Install]
WantedBy=multi-user.target
Step 4:
Run your service
as super user
$ systemctl start whatever_you_want.service # starts the service
$ systemctl enable whatever_you_want.service # auto starts the service
$ systemctl ...
Gradle to execute Java class (without modifying build.gradle)
...ATE
:classes
:execute
I am BOO!
mainClass is a property passed in dynamically at command line. classpath is set to pickup the latest classes.
If you do not pass in the mainClass property, both of the approaches fail as expected.
$ gradle execute
FAILURE: Build failed with an exception.
* Whe...
How to share my Docker-Image without using the Docker-Hub?
...ers are stored by default under /var/lib/docker. While you could (theoretically) cherry pick files from there and install it in a different docker server, is probably a bad idea to play with the internal representation used by Docker.
When you push your image, these layers are sent to the registry ...