Tutorial by Examples

Declared variable without a value will have the value undefined var a; console.log(a); // logs: undefined Trying to retrieve the value of undeclared variables results in a ReferenceError. However, both the type of undeclared and unitialized variables is "undefined": var a; console...

variables var = 50 -- a global variable print(var) --> 50 do local var = 100 -- a local variable print(var) --> 100 end print(var) --> 50 -- The global var (50) still exists -- The local var (100) has gone out of scope and can't be accessed any longer. types num = 20 -- a ...

A patch is a file that show the differences between two revisions or between your local repository and the last revision your repository is pointing. To share or save a patch of your local uncommitted changes either for peer review or to apply later, do: svn diff > new-feature.patch To get a...

Running svn log will show you all the commit messages, you probably want to review only certain revisions. View the n most recent revisions: svn log -n View a specific revision: svn log -c rXXX View the paths affected: svn log -v -c rXXX

The key in vectorizing R code, is to reduce or eliminate "by row operations" or method dispatching of R functions. That means that when approaching a problem that at first glance requires "by row operations", such as calculating the means of each row, one needs to ask themselves...

C99 These functions returns the floating-point remainder of the division of x/y. The returned value has the same sign as x. Single Precision: #include <math.h> /* for fmodf() */ #include <stdio.h> /* for printf() */ int main(void) { float x = 10.0; float y = 5.1; ...

function transform(fn, arr) { let result = []; for (let el of arr) { result.push(fn(el)); // We push the result of the transformed item to result } return result; } console.log(transform(x => x * 2, [1,2,3,4])); // [2, 4, 6, 8] As you can see, our transform fun...

Creating a managed table with partition and stored as a sequence file. The data format in the files is assumed to be field-delimited by Ctrl-A (^A) and row-delimited by newline. The below table is created in hive warehouse directory specified in value for the key hive.metastore.warehouse.dir in the ...

Creating a database in a particular location. If we dont specify any location for database its created in warehouse directory. CREATE DATABASE IF NOT EXISTS db_name COMMENT 'TEST DATABASE' LOCATION /PATH/HDFS/DATABASE/;

1. Passing integer data: SenderActivity Intent myIntent = new Intent(SenderActivity.this, ReceiverActivity.class); myIntent.putExtra("intVariableName", intValue); startActivity(myIntent); ReceiverActivity Intent mIntent = getIntent(); int intValue = mIntent.getIntExtra("intVa...

To change UI content in runtime, you can use Binding. When binded property is changed from the code, it will be displayed to the UI. <TextBlock Text="{Binding Title}"/> To notify UI about changes, property must raise PropertyChanged event from INotifyPropertyChanged interface or ...

// Add active class to active navigation link $(document).ready(function () { $('ul.nav.navbar-nav').find('a[href="' + location.pathname + '"]') .closest('li').addClass('active'); });

In addition to the concept of column units, Bootstrap has different breakpoints or grid sizes known as tiers. The Bootstrap 3 grid has four (4) tiers to accomodate different screen (or viewport) widths. The Bootstrap 3 tiers are xs, sm, md, and lg. Bootstrap’s grid columns are identified by differen...

If you're doing multiple long calculations, you can run them at the same time on different threads on your computer. To do this, we make a new Thread and have it point to a different method. using System.Threading; class MainClass { static void Main() { var thread = new Thread(Seco...

using System.Threading; class MainClass { static void Main() { var thread = new Thread(Secondary); thread.Start("SecondThread"); } static void Secondary(object threadName) { System.Console.WriteLine("Hello World from thread: " + thread...

Environment.ProcessorCount Gets the number of logical processors on the current machine. The CLR will then schedule each thread to a logical processor, this theoretically could mean each thread on a different logical processor, all threads on a single logical processor or some other combination...

Sometimes, you want your threads to simultaneously share data. When this happens it is important to be aware of the code and lock any parts that could go wrong. A simple example of two threads counting is shown below. Here is some dangerous (incorrect) code: using System.Threading; class MainCl...

If you have a foreach loop that you want to speed up and you don't mind what order the output is in, you can convert it to a parallel foreach loop by doing the following: using System; using System.Threading; using System.Threading.Tasks; public class MainClass { public static void Main...

Everything between /* and */ is commented. void main() { for (int i = 0; i < 5; i++) { /* This is commented, and will not affect code */ print('hello ${i + 1}'); } }

Using a doc comment instead of a regular comment enables dartdoc to find it and generate documentation for it. /// The number of characters in this chunk when unsplit. int get length => ... You are allowed to use most markdown formatting in your doc comments and dartdoc will process it accor...