Tutorial by Examples: nd

Sometimes we need to change type from Collection<T?> to Collections<T>. In that case, filterNotNull is our solution. val a: List<Int?> = listOf(1, 2, 3, null) val b: List<Int> = a.filterNotNull()

3 You can use rem defined by the font-size of your html tag to style elements by setting their font-size to a value of rem and use em inside the element to create elements that scale with your global font-size. HTML: <input type="button" value="Button"> <input type=...

This is a minimalist Hello World example that uses only the most basic Android tools. Requirements and assumptions Oracle JDK 1.7 or later Android SDK Tools (just the command line tools) This example assumes Linux. You may have to adjust the syntax for your own platform. Setting up the And...

This is MATLAB's long-winded way of saying that it cannot find the function that you're trying to call. There are a number of reasons you could get this error: That function was introduced after your current version of MATLAB The MATLAB online documentation provides a very nice feature which allow...

Undo changes to a file or directory in the working copy. git checkout -- file.txt Used over all file paths, recursively from the current directory, it will undo all changes in the working copy. git checkout -- . To only undo parts of the changes use --patch. You will be asked, for each chang...

Node.js has 3 basic ways to handle exceptions/errors: try-catch block error as the first argument to a callback emit an error event using eventEmitter try-catch is used to catch the exceptions thrown from the synchronous code execution. If the caller (or the caller's caller, ...) used try/ca...

Screen shot: Option 1 (pure adb) The shell adb command allows us to execute commands using a device's built-in shell. The screencap shell command captures the content currently visible on a device and saves it into a given image file, e.g. /sdcard/screen.png: adb shell screencap /sdcard/screen.png...

You may want to nest cached fragments inside other cached fragments. This is called Russian doll caching. The advantage of Russian doll caching is that if a single product is updated, all the other inner fragments can be reused when regenerating the outer fragment. As explained in the previous sec...

A has_and_belongs_to_many association creates a direct many-to-many connection with another model, with no intervening model. For example, if your application includes assemblies and parts, with each assembly having many parts and each part appearing in many assemblies, you could declare the models...

Rails have very easy way to get first and last record from database. To get the first record from users table we need to type following command: User.first It will generate following sql query: SELECT `users`.* FROM `users` ORDER BY `users`.`id` ASC LIMIT 1 And will return following recor...

GCD will guarantee that your singleton only gets instantiated once, even if called from multiple threads. Insert this into any class for a singleton instance called shared. + (instancetype)shared { // Variable that will point to the singleton instance. The `static` // modifier makes it ...

xml of the Dialog: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="mat...

You can rescue a RecordNotFound exception with a redirect instead of showing an error page: class ApplicationController < ActionController::Base # your other stuff rescue_from ActiveRecord::RecordNotFound do |exception| redirect_to root_path, 404, alert: I18n.t("errors.record...

Suppose you have multiple lines in the same plot, each of a different color, and you wish to make a legend to tell what each line represents. You can do this by passing on a label to each of the lines when you call plot(), e.g., the following line will be labelled "My Line 1". ax.plot(...

In the case of a multi-project gradle build, you may sometimes need to depend on another project in your build. To accomplish this, you'd enter the following in your project's dependencies: dependencies { compile project(':OtherProject') } Where ':OtherProject' is the gradle path for the p...

The Java language provides 4 operators that perform bitwise or logical operations on integer or boolean operands. The complement (~) operator is a unary operator that performs a bitwise or logical inversion of the bits of one operand; see JLS 15.15.5.. The AND (&) operator is a binary operat...

The following examples can be tested on https://ellie-app.com/m9vmQ8NcMc/0. import Html exposing (..) import Json.Decode payload = """ [ { "bark": true, "tag": "dog", "name": "Zap", "playful": true } , { "w...

The map operation is a useful tool when working with arrays and vectors, but it can also be used to deal with Option values in a functional way. fn main() { // We start with an Option value (Option<i32> in this case). let some_number = Some(9); // Let's do some consecutive ...

Exceptions in Laravel are handled by App\Exceptions\Handler.php This file contains two functions by default. Report & Render. We will only be using the first public function report(Exception $e) The report method is used to log exceptions or send them to an external service like BugSnag...

Circle To create a circle, define an element with an equal width and height (a square) and then set the border-radius property of this element to 50%. HTML <div class="circle"></div> CSS .circle { width: 50px; height: 50px; background: rgb(246, 156, 85); ...