Tutorial by Examples: g

7.0 OrElse Sub Main() Dim elements As List(Of Integer) = Nothing Dim average As Double = AverageElementsOrElse(elements) Console.WriteLine(average) ' Writes 0 to Console Try 'Throws ArgumentNullException average = AverageElementsOr(elements) Catch ex ...

using System; using System.Threading; using System.Threading.Tasks; class Program { static void Main( string[] args ) { object sync = new object(); int sum = 0; Parallel.For( 1, 1000, ( i ) => { lock( sync ) sum = sum + i; // lock is necessa...

Using the Library Database, we try to find the last book added to the database for each author. For this simple example we assume an always incrementing Id for each record added. SELECT MostRecentBook.Name, MostRecentBook.Title FROM ( SELECT Authors.Name, Books.Title, ...

As of Qt 5.1 and later you can use QQmlApplicationEngine instead of QQuickView to load and render a QML script. With QQmlApplicationEngine you do need to use a QML Window type as your root element. You can obtain the root context from the engine where you can then add global properties to the cont...

Creating a ServiceHost programmatically (without config file) in its most basic form: namespace ConsoleHost { class ConsoleHost { ServiceHost mHost; public Console() { mHost = new ServiceHost(typeof(Example), new Uri("net.tcp://localhost:9000/Example")); ...

class ClassWithAReallyLongName { public: class Iterator { /* ... */ }; Iterator end(); }; Defining the member end with a trailing return type: auto ClassWithAReallyLongName::end() -> Iterator { return Iterator(); } Defining the member end without a trailing return type: Clas...

>>> df ID Year Jan_salary Feb_salary Mar_salary 0 1 2016 4500 4200 4700 1 2 2016 3800 3600 4400 2 3 2016 5500 5200 5300 >>> melted_df = pd.melt(df,id_vars=['ID','Year'], v...

Create a MongoDB connection, that later you can query: $manager = new \MongoDB\Driver\Manager('mongodb://localhost:27017'); In the next example, you will learn how to query the connection object. This extension close the connection automatically, it's not necessary to close manually.

Example for searching just one user with a specific id, you should do: $options = ['limit' => 1]; $filter = ['_id' => new \MongoDB\BSON\ObjectID('578ff7c3648c940e008b457a')]; $query = new \MongoDB\Driver\Query($filter, $options); $cursor = $manager->executeQuery('database_name.collect...

Example for searching multiple users with the name "Mike": $filter = ['name' => 'Mike']; $query = new \MongoDB\Driver\Query($filter); $cursor = $manager->executeQuery('database_name.collection_name', $query); foreach ($cursor as $doc) { var_dump($doc); }

Navigation Drawers are used to navigate to top-level destinations in an app. Make sure that you have added design support library in your build.gradle file under dependencies: dependencies { // ... compile 'com.android.support:design:25.3.1' } Next, add the DrawerLayout and Navigati...

Comments are used to explain code when the basic code itself isn't clear. Python ignores comments, and so will not execute code in there, or raise syntax errors for plain english sentences. Single-line comments begin with the hash character (#) and are terminated by the end of line. Single lin...

Using range-base loops, you can loop over a sub-part of a given container or other range by generating a proxy object that qualifies for range-based for loops. template<class Iterator, class Sentinel=Iterator> struct range_t { Iterator b; Sentinel e; Iterator begin() const { return ...

select * from sys.dm_resource_governor_workload_groups select * from sys.dm_resource_governor_resource_pools

Given the following XML document: <documentation> <tags> <tag name="Java"> <topic name="Regular expressions"> <example>Matching groups</example> <example>Escaping metacharacter...

Sometimes specific instances of data should be used. Recreation is not desired and referencing static data would have a code smell. It is possible to specify a XmlAdapter instance the Unmarshaller should use, which allows the user to use XmlAdapters with no zero-arg constructor and/or pass data to ...

1 - Include the CoreLocation.framework in your project; this is accomplished by clicking on: root directory -> build phases -> Link Binary With Libraries Click on the (+) button, look for CoreLocation.framework and click add. 2- Modify the info.plist file to ask for permission to use user...

All parameters specified after the first asterisk in the function signature are keyword-only. def f(*a, b): pass f(1, 2, 3) # TypeError: f() missing 1 required keyword-only argument: 'b' In Python 3 it's possible to put a single asterisk in the function signature to ensure that the rema...

Prolog categorizes everything into: Atoms - Any sequence of characters that do not start with an uppercase alphabet. Eg - a, b, okay Numbers - There is no special syntax for numbers, no declaration is required. Eg 1, 22, 35.8 Variables - A string which starts with an uppercase character or unde...

Usually grep prints only matching lines. In the example below seq 9 generates a list of numbers from 1 to 9, one per line, and grep prints a single matching line: seq 9 | grep 5 # 5 The -C n option (or --context=n in long form) prints n lines before and after each matching line, in addition to ...