Tutorial by Examples: g

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(...

Database configuration of a rails project lies in a file config/database.yml. If you create a project using rails new command and don't specify a database engine to be used then rails uses sqlite as the default database. A typical database.yml file with default configuration will look similar to fol...

Callbacks offer a way to extend the functionality of a function (or method) without changing its code. This approach is often used in modules (libraries / plugins), the code of which is not supposed to be changed. Suppose we have written the following function, calculating the sum of a given array ...

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...

Testing your Active Record models through your command line interface is simple. Navigate to the app directory in your terminal and type in rails console to start the Rails console. From here, you can run active record methods on your database. For example, if you had a database schema with a User...

DISCLAIMER: Scaffolding is not recommended unless it's for very conventional CRUD apps/testing. This may generate a lot of files(views/models/controllers) that are not needed in your web application thus causing headaches(bad :(). To generate a fully working scaffold for a new object, including mod...

console.count([obj]) places a counter on the object's value provided as argument. Each time this method is invoked, the counter is increased (with the exception of the empty string ''). A label together with a number is displayed in the debugging console according to the following format: [label]: ...

Debug.log's second argument is always returned, so you could write code like the following and it would just work: update : Msg -> Model -> (Model, Cmd Msg) update msg model = case Debug.log "The Message" msg of Something -> ... Replacing case msg o...

Any lodash collection method has two syntaxes. Without chaining: var arr1 = [10, 15, 20, 25, 30, 15, 25, 35]; var arr2 = _.filter(arr1, function(item){ return item % 10 === 5 }); // arr2 now contains [15, 25, 15, 25, 35] var arr3 = _.uniq(arr2); // arr3 now contains [15, 25, 35] var arr...

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...

Easily add a heading container to your panel with .panel-heading. You may also include any <h1>-<h6> with a .panel-title class to add a pre-styled heading. However, the font sizes of <h1>-<h6> are overridden by .panel-heading. For proper link coloring, be sure to place links...

The following example can be tested on https://ellie-app.com/m9tk39VpQg/0. import Html exposing (..) import Json.Decode payload = """ ["fu", "bar"] """ main = Json.Decode.decodeString decoder payload -- Ok ["fu","b...

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...

Content scripts can be declared in manifest.json to be always injected into pages that match a set of URL patterns. Minimal example "content_scripts" : [ { "js": ["content.js"], "css": ["content.css"] "matches": [&quot...

If, instead of always having a content script injected based on the URL, you want to directly control when a content script is injected, you can use Programmatic Injection. Minimal example JavaScript chrome.tabs.executeScript({file: "content.js"}); CSS chrome.tabs.insert...

As Go uses implicit interface implementation, you will not get a compile-time error if your struct does not implement an interface you had intended to implement. You can test the implementation explicitly using type casting: type MyInterface interface { Thing() } type MyImplementer struct {} ...

First action to take is to create a new project File > New > Project. Here Single View Application is selected, but you can choose the one that fits your project the best. The next step in setup of core data is adding the information to your project. The important part in the photo below is...

First it is important to understand that the Core Data Model is the *.xcdatamodeld file. You will notice you have not entities. You will have to create one yourself. At the bottom of Xcode you will notice a button that says "Add Entity" click it and you will have a new entity in the ...

Under the attributes section you add the attributes to your model. This button is a plus located at the bottom of the section. You can add any attributes that are relevant to your app. You have several options of types to choose from ranging from Booleans to Dates and more. The Inspector panel also ...