Tutorial by Examples: r

Example: Customers who can create a post. Each customer can create multiple posts. As soon as customer creates the post, post will be under administrators review. Now we have to fetch the customers list who have all active posts by using sub-query. Note: If a customer has 5 post, among 5 posts if h...

Logs are very important. Recreate an error context can be sometimes very painful due to the lack of information about how and when the error occurred. This example shows: How to add user's data in the error logs How to add post parameters sent when an error occurred How to use WebPr...

Java Code import org.opencv.core.Mat; import org.opencv.core.MatOfRect; import org.opencv.core.Point; import org.opencv.core.Rect; import org.opencv.core.Scalar; import org.opencv.highgui.Highgui; import org.opencv.highgui.VideoCapture; import org.opencv.objdetect.CascadeClassifier; publ...

Use Nuget to install the Nancy and Nancy.Hosting.Self packages into the project. Instantiate a new NancyHost object and pass in the relevant URL using( var host = new NancyHost( hostConfiguration, new Uri( "http://localhost:1234" ) ) ) { host.Start(); Console.WriteLine( "Running o...

When you want to work with the data entries in arrays you first need to unwind the array. The unwind operation creates a document for each entry in the array. When you have lot's of documents with large arrays you will see an explosion in number of documents. { "_id" : 1, "item"...

_refreshControl(){ return ( <RefreshControl refreshing={this.state.refreshing} onRefresh={()=>this._refreshListView()} /> ) } refreshing: is the state of the spinner (true, false). onRefresh: this function will invoke when refresh the ListView/Scr...

_refreshListView(){ //Start Rendering Spinner this.setState({refreshing:true}) this.state.cars.push( {name:'Fusion',color:'Black'}, {name:'Yaris',color:'Blue'} ) //Updating the dataSource with new data this.setState({ dataSource: this.state.data...

RefreshControl is used inside a ScrollView or ListView to add pull to refresh functionality. at this example we will use it with ListView 'use strict' import React, { Component } from 'react'; import { StyleSheet, View, ListView, RefreshControl, Text } from 'react-native' class RefreshContr...

//Before: antipattern 3 global variables var setActivePage = function () {}; var getPage = function() {}; var redirectPage = function() {}; //After: just 1 global variable, no function collision and more meaningful function names var NavigationNs = NavigationNs || {}; N...

Let us assume we have the following two DataFrames: In [7]: df1 Out[7]: A B 0 a1 b1 1 a2 b2 In [8]: df2 Out[8]: B C 0 b1 c1 The two DataFrames are not required to have the same set of columns. The append method does not change either of the original DataFrames. Inst...

A common task for regex is to replace text that matches a pattern with a new value. #Sample text $text = @" This is (a) sample text, this is a (sample text) "@ #Sample pattern: Text wrapped in () $pattern = '\(.*?\)' #Replace matches with: $newvalue = 'test' Using -Replace...

Sometimes you need to replace a value matching a pattern with a new value that's based on that specific match, making it impossible to predict the new value. For these types of scenarios, a MatchEvaluator can be very useful. In PowerShell, a MatchEvaluator is as simple as a scriptblock with a singl...

A regex-pattern uses many special characters to describe a pattern. Ex., . means "any character", + is "one or more" etc. To use these characters, as a .,+ etc., in a pattern, you need to escape them to remove their special meaning. This is done by using the escape character whi...

Tuples are immutable ordered collections of arbitrary distinct objects, either of the same type or of different types. Typically, tuples are constructed using the (x, y) syntax. julia> tup = (1, 1.0, "Hello, World!") (1,1.0,"Hello, World!") The individual objects of a tup...

Tuples are frequently used for multiple return values. Much of the standard library, including two of the functions of the iterable interface (next and done), returns tuples containing two related but distinct values. The parentheses around tuples can be omitted in certain situations, making multip...

The IIF statement can be used in expressions to screen for division by zero: =IIF(Fields!PossibleZero.Value=0,0,Fields!Denominator.Value/IIF(Fields!PossibleZero.Value=0,1,Fields!PossibleZero.Value)) SSRS does not short circuit IIF arguments. Therefore, using a single IIF function to screen for ...

In order to use a plain-text editor to create a Console application that is written in C#, you'll need the C# Compiler. The C# Compiler (csc.exe), can be found at the following location: %WINDIR%\Microsoft.NET\Framework64\v4.0.30319\csc.exe N.B. Depending upon which version of the .NET Framework t...

svn2git is a Ruby wrapper around git's native SVN support through git-svn, helping you with migrating projects from Subversion to Git, keeping history (incl. trunk, tags and branches history). Examples To migrate a svn repository with the standard layout (ie. branches, tags and trunk at the root l...

Given a CLLocationDistance (simply a Double representing meters), output a user-readable string: let distance = CLLocationDistance(42) let formatter = MKDistanceFormatter() let answer = formatter.stringFromDistance(distance) // answer = "150 feet" Objective-C CLLocationDistance dis...

inputype attribute in EditText widget: (tested on Android 4.4.3 and 2.3.3) <EditText android:id="@+id/et_test" android:inputType="?????"/> textLongMessage= Keyboard: alphabet/default. Enter button: Send/Next. Emotion: yes. Case: lowercase. Suggestion: yes. Add. chars: ,...