Tutorial by Examples: t

class UsersController < ApplicationController def index respond_to do |format| format.html { render html: "Hello World" } end end end This is a basic controller, with the addition of the following route (in routes.rb): resources :users, only: [:index] Will...

Controllers have access to HTTP parameters (you might know them as ?name=foo in URLs, but Ruby on Rails handle different formats too!) and output different responses based on them. There isn't a way to distinguish between GET and POST parameters, but you shouldn't do that in any case. class UsersCo...

class UsersController < ApplicationController def index respond_to do |format| format.html do render html: "Hello #{ user_params[:name] } user_params[:sentence]" end end end private def user_params if params[:name] == "john&quo...

Assuming the route: resources :users, only: [:index] You can redirect to a different URL using: class UsersController def index redirect_to "http://stackoverflow.com/" end end You can go back to the previous page the user visited using: redirect_to :back Note that i...

This function runs an AJAX call using GET allowing us to send parameters (object) to a file (string) and launch a callback (function) when the request has been ended. function ajax(file, params, callback) { var url = file + '?'; // loop through object and assemble the url var notFirst ...

resources :photos do member do get 'preview' end collection do get 'dashboard' end end This creates the following routes in addition to default 7 RESTful routes: get '/photos/:id/preview', to: 'photos#preview' get '/photos/dashboards', to: '...

In JavaScript, all numbers are internally represented as floats. This means that simply using your integer as a float is all that must be done to convert it.

To convert a float to an integer, JavaScript provides multiple methods. The floor function returns the first integer less than or equal to the float. Math.floor(5.7); // 5 The ceil function returns the first integer greater than or equal to the float. Math.ceil(5.3); // 6 The round function...

#![feature(start, libc, lang_items)] #![no_std] #![no_main] // The libc crate allows importing functions from C. extern crate libc; // A list of C functions that are being imported extern { pub fn printf(format: *const u8, ...) -> i32; } #[no_mangle] // The main function, with...

From guides.rubyonrails.org: Instead of generating a model directly . . . let's set up a scaffold. A scaffold in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above. Here's a...

The StringBuffer, StringBuilder, Formatter and StringJoiner classes are Java SE utility classes that are primarily used for assembling strings from other information: The StringBuffer class has been present since Java 1.0, and provides a variety of methods for building and modifying a "buf...

git config --global merge.conflictstyle diff3 Sets the diff3 style as default: instead of the usual format in conflicted sections, showing the two files: <<<<<<< HEAD left ======= right >>>>>>> master it will include an additional section containi...

Rails files - and Ruby files in general - should be named with lower_snake_case filenames. E.g. app/controllers/application_controller.rb is the file that contains the ApplicationController class definition. Note that while PascalCase is used for class and module names, the files in which they r...

The following query returns the database options and metadata: select * from sys.databases WHERE name = 'MyDatabaseName';

parseFloat accepts a string as an argument which it converts to a float/ parseFloat("10.01") // = 10.01

// Generic types are declared using the <T> annotation struct GenericType<T> { pub item: T } enum QualityChecked<T> { Excellent(T), Good(T), // enum fields can be generics too Mediocre { product: T } }

// explicit type declaration let some_value: Option<u32> = Some(13); // implicit type declaration let some_other_value = Some(66);

Generics types can have more than one type parameters, eg. Result is defined like this: pub enum Result<T, E> { Ok(T), Err(E), }

// Only accept T and U generic types that also implement Debug fn print_objects<T: Debug, U: Debug>(a: T, b: U) { println!("A: {:?} B: {:?}", a, b); } print_objects(13, 44); // or annotated explicitly print_objects::<usize, u16>(13, 44); The bounds must cover a...

Generic functions allow some or all of their arguments to be parameterised. fn convert_values<T, U>(input_value: T) -> Result<U, String> { // Try and convert the value. // Actual code will require bounds on the types T, U to be able to do something with them. } If the compi...