Tutorial by Examples: v

Interface declaration for downloading a file public interface ApiInterface { @GET("movie/now_playing") Call<MovieResponse> getNowPlayingMovies(@Query("api_key") String apiKey, @Query("page") int page); // option 1: a resource relative to your bas...

Singleton classes share their instance/class variables with their object. class Example @@foo = :example end def Example.foo class_variable_get :@@foo end Example.foo #=> :example class Example def initialize @foo = 1 end def foo @foo end end e = Ex...

0.18.0 Model is passed to subscriptions which means that every state change can modify subscriptions. import Html exposing ( Html, div, text, button ) import Html.Events exposing ( onClick ) import Time main : Program Never Model Msg main = Html.program { init = init ,...

The canvas can be used to display video from a variety of sources. This example shows how to load a video as a file resource, display it and add a simple click on screen play/pause toggle. This stackoverflow self answered question How do I display a video using HTML5 canvas tag shows the following ...

If a recursive call goes "too deep", this results in a StackOverflowError. Java allocates a new frame for every method call on its thread's stack. However, the space of each thread's stack is limited. Too many frames on the stack leads to the Stack Overflow (SO). Example public static vo...

A common issue that users of Eclipse encounter is related to the default system JVM. A typical situation is a 64 bit Windows which has both 32 and 64 bit versions of Java installed, and a 32 bit Eclipse. If the 64 bit version of Java is the system default, when Eclipse is launched an error dialog i...

x IN ( SELECT ... ) turn into a JOIN When possible, avoid OR. Do not 'hide' an indexed column in a function, such as WHERE DATE(x) = ...; reformulate as WHERE x = ... You can generally avoid WHERE LCASE(name1) = LCASE(name2) by having a suitable collation. Do no use OFFSET for "paginatio...

Here are some things that are not likely to help performance. They stem from out-of-date information and/or naivety. InnoDB has improved to the point where MyISAM is unlikely to be better. PARTITIONing rarely provides performance benefits; it can even hurt performance. Setting query_cache_size...

Example below shows how to create a BroadcastReceiver which is able to receive BOOT_COMPLETED events. This way, you are able to start a Service or start an Activity as soon device was powered up. Also, you can use BOOT_COMPLETED events to restore your alarms since they are destroyed when device is ...

For the sake of this example, let us assume that we have a server for handling the POST requests that we will be making from our Android app: // User input data. String email = "[email protected]"; String password = "123"; // Our server URL for handling POST requests. String UR...

The pointer-events property allows for control over how HTML elements respond to mouse/touch events. .disabled { pointer-events: none; } In this example, 'none' prevents all click, state and cursor options on the specified HTML element [[1]] Other valid values for HTMl elements are: ...

Sometimes you may need to validate record only under certain conditions. class User < ApplicationRecord validates :name, presence: true, if: :admin? def admin? conditional here that returns boolean value end end If you conditional is really small, you can use a Proc: class ...

Imagine that we have a separate Google spreadsheet, and we need to get the B2 cell value to cell D5 on your current sheet. function copyValueandPaste() { var source = SpreadsheetApp.openById('spread sheet id is here'); //Separate spreadsheet book var sourcesheet = source.getSheetByName...

As with docopt, with [docopt_dispatch] you craft your --help in the __doc__ variable of your entry-point module. There, you call dispatch with the doc string as argument, so it can run the parser over it. That being done, instead of handling manually the arguments (which usually ends up in a high c...

Consider the following naive method for adding two positive numbers using recursion: public static int add(int a, int b) { if (a == 0) { return b; } else { return add(a - 1, b + 1); // TAIL CALL } } This is algorithmically correct, but it has a major problem. ...

Mysql has its EVENT functionality for avoiding complicated cron interactions when much of what you are scheduling is SQL related, and less file related. See the Manual page here. Think of Events as Stored Procedures that are scheduled to run on recurring intervals. To save time in debugging Event-r...

PHP 5.5 introduces Generators and the yield keyword, which allows us to write asynchronous code that looks more like synchronous code. The yield expression is responsible for giving control back to the calling code and providing a point of resumption at that place. One can send a value along the yi...

Icicle uses Awaitables and Generators to create Coroutines. require __DIR__ . '/vendor/autoload.php'; use Icicle\Awaitable; use Icicle\Coroutine\Coroutine; use Icicle\Loop; $generator = function (float $time) { try { // Sets $start to the value returned by microtime() after ap...

Unzipping a zip archive is done with unzip function from the utils package (which is included in base R). unzip(zipfile = "bar.zip", exdir = "./foo") This will extract all files in "bar.zip" to the "foo" directory, which will be created if necessary. Tilde...

Listing files in a zip archive is done with unzip function from the utils package (which is included in base R). unzip(zipfile = "bar.zip", list = TRUE) This will list all files in "bar.zip" and extract none. Tilde expansion is done automatically from your working directory. ...