Tutorial by Examples: v

The reason you do not have to override Awake, Start, Update and other method is because they are not virtual methods defined in a base class. The first time your script gets accessed, the scripting runtime looks through the script to see if some methods are defined. If they are, that information is...

To forbid null values in your table columns, add the :null parameter to your migration, like this: class AddPriceToProducts < ActiveRecord::Migration def change add_column :products, :float, null: false end end

In order to have google maps work properly with turbolinks, add the javascript tag directly to the layout header rather than including it in a view. # app/views/layouts/my_layout.html.haml !!! %html{:lang => 'en'} %head - # ... = google_maps_api_script_tag The google_maps_api_s...

On the profile view, show the profile fields of a user or group in a list as well as the address fields on a google map. - # app/views/profiles/show.html.haml %h1 Contact Information .profile_fields = render @profile_fields .google_map{data: address_fields: @address_fields.to_json } The ap...

Suppose, there is a .google_map div, which will become the map, and which has the address fields to show as markers as data attribute. For example: <!-- http://localhost:3000/profiles/123 --> <div class="google_map" data-address-fields="[ {label: 'Work address', value: ...

If you need to search an ActiveRecord model for similar values, you might be tempted to use LIKE or ILIKE but this isn't portable between database engines. Similarly, resorting to always downcasing or upcasing can create performance issues. You can use ActiveRecord's underlying Arel matches method...

Start using File Uploads in Rails is quite simple, first thing you have to do is to choice plugin for managing uploads. The most common onces are Carrierwave and Paperclip. Both are similar in functionality and rich in documentation on Let's have an look on example with simple avatar upload image w...

added in GHC 7.8. OverloadedLists, similar to OverloadedStrings, allows list literals to be desugared as follows: [] -- fromListN 0 [] [x] -- fromListN 1 (x : []) [x .. ] -- fromList (enumFrom x) This comes handy when dealing with types such as Set, Vector and Maps. ['0'...

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...

Configuration files for rails can be found in config/environments/. By default rails has 3 environments, development, production and test. By editing each file you are editing the configuration for that environment only. Rails also has a configuration file in config/application.rb. This is a common...

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...

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...

There are two basic styles of type conversion in Go: // Simple type conversion var x := Foo{} // x is of type Foo var y := (Bar)Foo // y is of type Bar, unless Foo cannot be cast to Bar, then compile-time error occurs. // Extended type conversion var z,ok := x.(Bar) // z is of type Bar, o...

To add a value to a Set, use the .add() method: mySet.add(5); If the value already exist in the set it will not be added again, as Sets contain unique values. Note that the .add() method returns the set itself, so you can chain add calls together: mySet.add(1).add(2).add(3);

To remove a value from a set, use .delete() method: mySet.delete(some_val); This function will return true if the value existed in the set and was removed, or false otherwise.

To check if a given value exists in a set, use .has() method: mySet.has(someVal); Will return true if someVal appears in the set, false otherwise.

use std::fs::File; use std::io::Read; fn read_a_file() -> std::io::Result<Vec<u8>> { let mut file = try!(File::open("example.data")); let mut data = Vec::new(); try!(file.read_to_end(&mut data)); return Ok(data); } std::io::Result<T>...

1) Form Request Validation You may create a "form request" which can hold the authorization logic, validation rules, and error messages for a particular request in your application. The make:request Artisan CLI command generates the class and places it in the app/Http/Requests director...

One common use for the FOR XML function is to concatenate the values of multiple rows. Here's an example using the Customers table: SELECT STUFF( (SELECT ';' + Email FROM Customers where (Email is not null and Email <> '') ORDER BY Email ASC FOR XM...

The value of iota is still incremented for every entry in a constant list even if iota is not used: const ( // iota is reset to 0 a = 1 << iota // a == 1 b = 1 << iota // b == 2 c = 3 // c == 3 (iota is not used but still incremented) d = 1 << iota ...