Tutorial by Examples: le

Once the instance of the BackgroundWorker has been declared, it must be given properties and event handlers for the tasks it performs. /* This is the backgroundworker's "DoWork" event handler. This method is what will contain all the work you wish to have your progra...

The following example demonstrates the use of a BackgroundWorker to update a WinForms ProgressBar. The backgroundWorker will update the value of the progress bar without blocking the UI thread, thus showing a reactive UI while work is done in the background. namespace BgWorkerExample { public...

Elements come with angle brackets are the most prominent building block of XML. Elements can either be empty, in which case they are made of an empty tag (notice the ending slash): <an-empty-element/> Or they can have content, in which case they have an opening tag (no slash) and a closin...

The foreach package brings the power of parallel processing to R. But before you want to use multi core CPUs you have to assign a multi core cluster. The doSNOW package is one possibility. A simple use of the foreach loop is to calculate the sum of the square root and the square of all numbers from...

These two documents are semantically equivalement, as namespaces matter, not prefixes. <?xml version="1.0"?> <myns:foo xmlns:myns="http://www.example.com/my-namespace"> </myns:foo> <?xml version="1.0"?> <ns:foo xmlns:ns="http://www...

import pandas as pd Create a DataFrame from a dictionary, containing two columns: numbers and colors. Each key represent a column name and the value is a series of data, the content of the column: df = pd.DataFrame({'numbers': [1, 2, 3], 'colors': ['red', 'white', 'blue']}) Show contents of d...

Create a DataFrame of random numbers: import numpy as np import pandas as pd # Set the seed for a reproducible sample np.random.seed(0) df = pd.DataFrame(np.random.randn(5, 3), columns=list('ABC')) print(df) # Output: # A B C # 0 1.764052 0.400157 0.9787...

Single line comments are preceded by --, and go until the end of the line: SELECT * FROM Employees -- this is a comment WHERE FName = 'John'

As Handlers are used to send Messages and Runnables to a Thread's message queue it's easy to implement event based communication between multiple Threads. Every Thread that has a Looper is able to receive and process messages. A HandlerThread is a Thread that implements such a Looper, for example th...

Use Ctrl + C, Ctrl + C to exit iex(1)> BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded (v)ersion (k)ill (D)b-tables (d)istribution Use Ctrl+ \ to immediately exit

g$ The above matches one letter (the letter g) at the end of a string in most regex engines (not in Oniguruma, where the $ anchor matches the end of a line by default, and the m (MULTILINE) modifier is used to make a . match any characters including line break characters, as a DOTALL modifier in ...

my $filename = '/path/to/file'; open my $fh, '<', $filename or die "Failed to open file: $filename"; # You can then either read the file one line at a time... while(chomp(my $line = <$fh>)) { print $line . "\n"; } # ...or read whole file into an arra...

Subqueries can also be used in the SELECT part of the outer query. The following query shows all weather table columns with the corresponding states from the cities table. SELECT w.*, (SELECT c.state FROM cities AS c WHERE c.name = w.city ) AS state FROM weather AS w;

b = {:ok, 1, 2} Tuples are the equivalent of arrays in other languages. They are stored contiguously in memory.

You can broadcast more complex messages by serializing the payload before you publish it: // definition of a message public class ChatMessage { public Guid Id { get; set; } public string User { get; set; } public string Text { get; set; } } // grab an instance of an ISubscriber...

StackExchange.Redis also supports sending bytes over the pub/sub channel, here we use protobuf-net to serialize our message to a byte array before sending it: // definition of a message (marked up with Protobuf attributes) [ProtoContract] public class ChatMessage { [ProtoMember(1)] pub...

One (or two) of the coolest new features in recent Xcode releases are the IBInspectable properties and IBDesignable UIViews. These have nothing to do with the functionality of your application but instead impact the developer experience in Xcode. The goal is to be able to visually inspect custom v...

SELECT e.Fname, e.LName FROM Employees e The Employees table is given the alias 'e' directly after the table name. This helps remove ambiguity in scenarios where multiple tables have the same field name and you need to be specific as to which table you want to return data from. SELECT e.Fname,...

Below you could find the table Employees with a reference to the table Cities. CREATE TABLE Cities( CityID INT IDENTITY(1,1) NOT NULL, Name VARCHAR(20) NOT NULL, Zip VARCHAR(10) NOT NULL ); CREATE TABLE Employees( EmployeeID INT IDENTITY (1,1) NOT NULL, FirstName VARCHA...

Read text file from path: val sc: org.apache.spark.SparkContext = ??? sc.textFile(path="/path/to/input/file") Read files using wildcards: sc.textFile(path="/path/to/*/*") Read files specifying minimum number of partitions: sc.textFile(path="/path/to/input/file&qu...