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Build yourself three servers using whatever physical or virtual hardware you wish. (This tutorial assumes you're using Ubuntu as your operating system.) Then repeat the following instructions three times... once for each server. # add the names of each server to the host file of each server sudo n...

Then go into the mongo shell and initiate the replica set, like so: meteor mongo > rs.initiate() PRIMARY> rs.add("mongo-a") PRIMARY> rs.add("mongo-b") PRIMARY> rs.add("mongo-c") PRIMARY> rs.setReadPref('secondaryPreferred')

PMF FOR THE BINOMIAL DISTRIBUTION Suppose that a fair die is rolled 10 times. What is the probability of throwing exactly two sixes? You can answer the question using the dbinom function: > dbinom(2, 10, 1/6) [1] 0.29071 PMF FOR THE POISSON DISTRIBUTION The number of sandwhich ordered in ...

General Using the package RMySQL we can easily query MySQL as well as MariaDB databases and store the result in an R dataframe: library(RMySQL) mydb <- dbConnect(MySQL(), user='user', password='password', dbname='dbname',host='127.0.0.1') queryString <- "SELECT * FROM table1 t1 JO...

Knitr is an R package that allows us to intermingle R code with LaTeX code. One way to achieve this is external code chunks. External code chunks allow us to develop/test R Scripts in an R development environment and then include the results in a report. It is a powerful organizational technique....

FunctionWidgetactionButtonAction ButtoncheckboxGroupInputA group of check boxescheckboxInputA single check boxdateInputA calendar to aid date selectiondateRangeInputA pair of calendars for selecting a date rangefileInputA file upload control wizardhelpTextHelp text that can be added to an input form...

A very useful feature many people overlook is the ability to construct a Map using a SOQL query. Map<Id, Account> accounts = new Map<Id, Account>([SELECT Id, Name FROM Account]); System.debug(accounts); When you run this code, accounts then contains a Map of your Account objects, ke...

Sorting arrays can be easily done with the Arrays api. import java.util.Arrays; // creating an array with integers int[] array = {7, 4, 2, 1, 19}; // this is the sorting part just one function ready to be used Arrays.sort(array); // prints [1, 2, 4, 7, 19] System.out.println(Arrays.toString...

Instead of struct IShape { virtual ~IShape() = default; virtual void print() const = 0; virtual double area() const = 0; virtual double perimeter() const = 0; // .. and so on }; Visitors can be used: // The concrete shapes struct Square; struct Circle; // The v...

We try to extract imdb top chart movies and ratings R> library(RCurl) R> library(XML) R> url <- "http://www.imdb.com/chart/top" R> top <- getURL(url) R> parsed_top <- htmlParse(top, encoding = "UTF-8") R> top_table <- readHTMLTable(parsed_top)[...

You can clear the console window using the console.clear() method. This removes all previously printed messages in the console and may print a message like "Console was cleared" in some environments.

The SilverStripe Grid Field Extensions Module has some very nice features to enhance the basic GridField... GridFieldAddExistingSearchButton - a more advanced search form for adding items GridFieldAddNewInlineButton - builds on GridFieldEditableColumns to allow inline creation of records. GridF...

The module Better Buttons for GridField adds new form actions and buttons to the GridField detail form. Save and add another: Create a record, and go right to adding another one, without having to click the back button, and then add again Save and close: Save the record and go back to list view ...

Intuition The categorical product of two types A and B should contain the minimal information necessary to contain inside an instance of type A or type B. We can see now that the intuitive coproduct of two types should be Either a b. Other candidates, such as Either a (b,Bool), would contain a part...

(This example copied from this StackOverflow answer) Let's say you have a number of different data types that all ought to have a lens with the same name, in this case capacity. The makeFields slice will create a class that accomplish this without namespace conflicts. {-# LANGUAGE FunctionalDepen...

First thing to do is enable the mod rewrite on wamp go to Apache modules and scroll down the list If not showing tick enable it and then restart all servers. Linux users can also use below terminal command to enable rewrite module sudo a2enmod rewrite Then restart apache using: sudo service...

Chaining and Chainable is a design methodology used to design object behaviors so that calls to object functions return references to self, or another object, providing access to additional function calls allowing the calling statement to chain together many calls without the need to reference the v...

Paste your fonts file inside android/app/src/main/assets/fonts/font_name.ttf Recompile the Android app by running react-native run-android Now, You can use fontFamily: 'font_name' in your React Native Styles

Cost centers are annotations on a Haskell program which can be added automatically by the GHC compiler -- using -fprot-auto -- or by a programmer using {-# SCC "name" #-} <expression>, where "name" is any name you wish and <expression> is any valid Haskell expression:...

Similar to currying, partial application is used to reduce the number of arguments passed to a function. Unlike currying, the number need not go down by one. Example: This function ... function multiplyThenAdd(a, b, c) { return a * b + c; } ... can be used to create another function that...