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Map and Filter Over A Collection

Map 'Mapping' across a collection uses the map function to transform each element of that collection in a similar way. The general syntax is: val someFunction: (A) => (B) = ??? collection.map(someFunction) You can provide an anonymous function: collection.map((x: T) => /*Do something wi...

Using Single Slots

Single slots are used when a child component only defines one slot within its template. The page component above uses a single slot to distribute content. An example of the page component's template using a single slot is below: <html> <head> <title>Page Title</t...

What are slots?

Slots offer a convenient way of distributing content from a parent component to a child component. This content can be anything from text, HTML or even other components. It can be helpful sometimes to think of slots as a means of injecting content directly into a child component's template. Slots ...

Using Named Slots

Named slots work similarly to single slots but instead allow you to distribute content to different regions within your child component template. Take the page component from the previous example but modify it's template so it is as follows: <html> <head> <title>Pag...

Namespace variables

The variable command ensures that a given namespace variable is created. Until a value is assigned to it, the variable's value is undefined: namespace eval mynamespace { variable alpha set alpha 0 } The variable can be accessed from outside the namespace (from anywhere, in fact) by at...

Deploying your application

Make sure you are in the directory that contains your Rails app, then create an app on Heroku. $ heroku create example Creating ⬢ example... done https://example.herokuapp.com/ | https://git.heroku.com/example.git The first URL of the ouput, http://example.herokuapp.com, is the location the ap...

Check matching fields in two files

Given these two CSV files: $ cat file1 1,line1 2,line2 3,line3 4,line4 $ cat file2 1,line3 2,line4 3,line5 4,line6 To print those lines in file2 whose second column occurs also in the first file we can say: $ awk -F, 'FNR==NR {lines[$2]; next} $2 in lines' file1 file2 1,line3 2,line4...

Installation or Setup

Download and install the WiX Toolset from wixtoolset.org. The installer for the WiX Toolset provides also the integration with Visual Studio, after the installation you should be able to create WiX specific projects. Warnings Admin rights are needed. Some versions of WiX are compatible only with...

Installation or Setup

Detailed instructions on getting asp.net-identity set up or installed.

Gradle Parallel builds

Gradle will only run one task at a time by default, regardless of the project structure. By using the --parallel switch, you can force Gradle to execute independent subprojects - those that have no implicit or explicit project dependencies between one another - in parallel, allowing it to run multip...

Use latest Gradle version

The Gradle team works regularly on improving the performance of different aspects of Gradle builds. If you’re using an old version of Gradle, you’re missing out on the benefits of that work. Try upgrading to the latest version of Gradle to see what kind of impact it has. Doing so is low risk because...

Split routes into multiple files

If your routes file is overwhelmingly big, you can put your routes in multiple files and include each of the files with Ruby’s require_relative method: config/routes.rb: YourAppName::Application.routes.draw do require_relative 'routes/admin_routes' require_relative 'routes/sidekiq_routes' ...

Ignoring return values of library functions

Almost every function in C standard library returns something on success, and something else on error. For example, malloc will return a pointer to the memory block allocated by the function on success, and, if the function failed to allocate the requested block of memory, a null pointer. So you sho...

Installation or Setup

On Windows Download the Visual Studio Code installer for Windows. Once it is downloaded, run the installer (VSCodeSetup-version.exe). This will only take a minute. By default, VS Code is installed under C:\Program Files (x86)\Microsoft VS Code for a 64-bit machine. Note: .NET Framework 4.5.2...

Core Extensions: String Exclusion

String#exclude? The inverse of String#include? "hello".exclude? "lo" # => false "hello".exclude? "ol" # => true "hello".exclude? ?h # => false

Core Extensions: String Filters

String#squish Returns a version of the given string without leading or trailing whitespace, and combines all consecutive whitespace in the interior to single spaces. Destructive version squish! operates directly on the string instance. Handles both ASCII and Unicode whitespace. %{ Multi-line ...

Core Extensions: String Inflection

String#pluralize Returns of plural form of the string. Optionally takes a count parameter and returns singular form if count == 1. Also accepts a locale parameter for language-specific pluralization. 'post'.pluralize # => "posts" 'octopus'.pluralize # => &quot...

Newline character is not consumed in typical scanf() call

When this program #include <stdio.h> #include <string.h> int main(void) { int num = 0; char str[128], *lf; scanf("%d", &num); fgets(str, sizeof(str), stdin); if ((lf = strchr(str, '\n')) != NULL) *lf = '\0'; printf("%d \"%s\&...

Adding a NOT NULL constraint to existing data

Say you want to add a foreign key company_id to the users table, and you want to have a NOT NULL constraint on it. If you already have data in users, you will have to do this in multiple steps. class AddCompanyIdToUsers < ActiveRecord::Migration def up # add the column with NULL allowed ...

Minimal Chart Example

Depending on the version of Chart.JS you are using (the current one being 2.X), the syntax is different to create a minimal example of a bar chart (JSFiddle Demo for 2.X). Chart.js 2.X <html> <body> <canvas id="myChart" width="400" height="400&...

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