Tutorial by Examples: ect

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...

PowerShell, unlike some other scripting languages, sends objects through the pipeline. What this means is that when you send data from one command to another, it's essential to be able to create, modify, and collect objects. Creating an object is simple. Most objects you create will be custom obj...

The Object.assign() method is used to copy the values of all enumerable own properties from one or more source objects to a target object. It will return the target object. Use it to assign values to an existing object: var user = { firstName: "John" }; Object.assign(user, {last...

Model with ForeignKey We will work with these models : from django.db import models class Book(models.Model): name= models.CharField(max_length=50) author = models.ForeignKey(Author) class Author(models.Model): name = models.CharField(max_length=50) Suppose we often (always) access ...

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...

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...

public static Unsafe getUnsafe() { try { Field unsafe = Unsafe.class.getDeclaredField("theUnsafe"); unsafe.setAccessible(true); return (Unsafe) unsafe.get(null); } catch (IllegalAccessException e) { // Handle } catch (IllegalArgumentExcept...

Use this option if you don't need an Application subclass. This is the simplest option, but this way you can't provide your own Application subclass. If an Application subclass is needed, you will have to switch to one of the other options to do so. For this option, simply specify the fully-quali...

When you do a groupby you can select either a single column or a list of columns: In [11]: df = pd.DataFrame([[1, 1, 2], [1, 2, 3], [2, 3, 4]], columns=["A", "B", "C"]) In [12]: df Out[12]: A B C 0 1 1 2 1 1 2 3 2 2 3 4 In [13]: g = df.groupby(...

You can mix normal parameters and parameter arrays: public class LotteryTicket : IEnumerable{ public int[] LuckyNumbers; public string UserName; public void Add(string userName, params int[] luckyNumbers){ UserName = userName; Lottery = luckyNumbers; } } ...

/** * Created by Alex Sullivan on 7/21/16. */ public class Foo implements Parcelable { private final int myFirstVariable; private final String mySecondVariable; private final long myThirdVariable; public Foo(int myFirstVariable, String mySecondVariable, long myThirdVariab...

import "reflect" value := reflect.ValueOf(4) // Interface returns an interface{}-typed value, which can be type-asserted value.Interface().(int) // 4 // Type gets the reflect.Type, which contains runtime type information about // this value value.Type().Name() // int value.SetInt(5)...

import "reflect" // this is effectively a pointer dereference x := 5 ptr := reflect.ValueOf(&x) ptr.Type().Name() // *int ptr.Type().Kind() // reflect.Ptr ptr.Interface() // [pointer to x] ptr.Set(4) // panic value := ptr.Elem() // this is a deref value.Type().Name() // int...

You can install Json.Net into your Visual Studio Project in 1 of 2 ways. Install Json.Net using the Package Manager Console. Open the Package Manager Console window in Visual Studio either by typing package manager console in the Quick Launch box and selecting it or by clicking View -> O...

Select Case can be used when many different conditions are possible. The conditions are checked from top to bottom and only the first case that match will be executed. Sub TestCase() Dim MyVar As String Select Case MyVar 'We Select the Variable MyVar to Work with Case "...

Set the MONGO_URL environment variable before starting your local Meteor app. Linux/MacOS Example: MONGO_URL="mongodb://some-mongo-host.com:1234/mydatabase" meteor or export MONGO_URL="mongodb://some-mongo-host.com:1234/mydatabase" meteor Windows Example Note: don't u...

The web.config system.web.httpRuntime must target 4.5 to ensure the thread will renter the request context before resuming your async method. <httpRuntime targetFramework="4.5" /> Async and await have undefined behavior on ASP.NET prior to 4.5. Async / await will resume on an arb...

Current file You can get the name of the current PHP file (with the absolute path) using the __FILE__ magic constant. This is most often used as a logging/debugging technique. echo "We are in the file:" , __FILE__ , "\n"; Current directory To get the absolute path to the di...

You can destructure nested vectors: (def my-vec [[1 2] [3 4]]) (let [[[a b][c d]] my-vec] (println a b c d)) ;; 1 2 3 4

The Flex compiler (mxmlc) is one of the most important parts of the Flex SDK. You can edit AS3 code in any text editor you like. Create a main class file that extends from DisplayObject. You can trigger builds at the command line as follows: mxmlc -source-path="." -default-size [width in...