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Each of the enum members may be initialized with a value. If a value is not specified for a member, by default it's initialized to 0 (if it's the first member in the member list) or to a value greater by 1 than the value of the preceding member. Module Module1 Enum Size Small ...

To set up a controller with user authentication using devise, add this before_action: (assuming your devise model is 'User'): before_action :authenticate_user! To verify if a user is signed in, use the following helper: user_signed_in? For the current signed-in user, use this helper: current_us...

There is also a way to have a single method accept a covariant argument, instead of having the whole trait covariant. This may be necessary because you would like to use T in a contravariant position, but still have it covariant. trait LocalVariance[T]{ /// ??? throws a NotImplementedError de...

Omitting the return statement in a function which is has a return type that is not void is undefined behavior. int function() { // Missing return statement } int main() { function(); //Undefined Behavior } Most modern day compilers emit a warning at compile time for this kind o...

Events that work with most form elements (e.g., change, keydown, keyup, keypress) do not work with contenteditable. Instead, you can listen to changes of contenteditable contents with the input event. Assuming contenteditableHtmlElement is a JS DOM object that is contenteditable: contenteditableH...

It is best practice in any programming language to avoid premature optimization. However, if testing reveals that your code is running too slowly, you may gain some speed by switching off some of the application’s properties while it runs. Add this code to a standard module: Public Sub SpeedUp( _ ...

%{username: username} = %{username: "John Doe", id: 1} # username == "John Doe" %{username: username, id: 2} = %{username: "John Doe", id: 1} ** (MatchError) no match of right hand side value: %{id: 1, username: "John Doe"}

// A simple adder function defined as a lambda expression. // Unlike with regular functions, parameter types often may be omitted because the // compiler can infer their types let adder = |a, b| a + b; // Lambdas can span across multiple lines, like normal functions. let multiplier = |a: i32, ...

Returning lambdas (or closures) from functions can be tricky because they implement traits and thus their exact size is rarely known. // Box in the return type moves the function from the stack to the heap fn curried_adder(a: i32) -> Box<Fn(i32) -> i32> { // 'move' applies move se...

If no ordering function is passed, std::sort will order the elements by calling operator< on pairs of elements, which must return a type contextually convertible to bool (or just bool). Basic types (integers, floats, pointers etc) have already build in comparison operators. We can overload this ...

// Include sequence containers #include <vector> #include <deque> #include <list> // Insert sorting algorithm #include <algorithm> class Base { public: // Constructor that set variable to the value of v Base(int v): variable(v) { } i...

C++11 // Include sequence containers #include <vector> #include <deque> #include <list> #include <array> #include <forward_list> // Include sorting algorithm #include <algorithm> class Base { public: // Constructor that set variable to the va...

BigInteger is in an immutable object, so you need to assign the results of any mathematical operation, to a new BigInteger instance. Addition: 10 + 10 = 20 BigInteger value1 = new BigInteger("10"); BigInteger value2 = new BigInteger("10"); BigInteger sum = value1.add(value...

You can access each property that belongs to an object with this loop for (var property in object) { // always check if an object has a property if (object.hasOwnProperty(property)) { // do stuff } } You should include the additional check for hasOwnProperty because an o...

pip may be used to install BeautifulSoup. To install Version 4 of BeautifulSoup, run the command: pip install beautifulsoup4 Be aware that the package name is beautifulsoup4 instead of beautifulsoup, the latter name stands for old release, see old beautifulsoup

A belongs_to association sets up a one-to-one connection with another model, so each instance of the declaring model "belongs to" one instance of the other model. For example, if your application includes users and posts, and each post can be assigned to exactly one user, you'd declare th...

A has_one association sets up a one-to-one connection with another model, but with different semantics. This association indicates that each instance of a model contains or possesses one instance of another model. For example, if each user in your application has only one account, you'd declare the...

DataFrame: import pandas as pd import numpy as np np.random.seed(5) df = pd.DataFrame(np.random.randint(100, size=(5, 5)), columns = list("ABCDE"), index = ["R" + str(i) for i in range(5)]) df Out[12]: A B C D E R0 99 78 61 16 73...

Alamofire.request("https://httpbin.org/get").validate().responseJSON { response in switch response.result { case .success: print("Validation Successful") case .failure(let error): print(error) } }

Alamofire.request(.GET, "https://httpbin.org/get", parameters: ["foo": "bar"]) .responseJSON { response in print(response.request) // original URL request print(response.response) // URL response print(response.data) // server da...