Tutorial by Examples: s

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 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 ...

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...

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...

Processing tabular data with awk is very easy, provided that the input is correctly formatted. Most software producing tabular data use specific features of this family of formats, and awk programs processing tabular data are often specific to a data produced by a specific software. If a more gener...

Given a file using ; as a column delimiter. Permuting the first and the second column is accomplished by awk -F';' -v 'OFS=;' '{ swap = $2; $2 = $1; $1 = swap; print }'

Given a file using ; as a column delimiter. We compute the mean of the values in the second column with the following program, the provided input is the list of grades of a student group: awk -F';' '{ sum += $2 } END { print(sum / NR) }' <<EOF Alice;2 Victor;1 Barbara;1 Casper;4 Deborah;...

We assume a file using ; as a column delimiter. Selecting a specific set of columns only requires a print statement. For instance, the following program selects the columns 3, 4 and 7 from its input: awk -F';' -v 'OFS=;' '{ print $3, $4, $7 }' It is as usual possible to more carefully choose lin...

Given a file using ; as a column delimiter. We compute the median of the values in the second column with the following program, written for GNU awk. The provided input is the list of grades of a student group: gawk -F';' '{ sample[NR] = $2 } END { asort(sample); if(NR % 2 == 1) { p...

There are two main ways to create an axes in matplotlib: using pyplot, or using the object-oriented API. Using pyplot: import matplotlib.pyplot as plt ax = plt.subplot(3, 2, 1) # 3 rows, 2 columns, the first subplot Using the object-oriented API: import matplotlib.pyplot as plt fig = ...

Use import to specify how a namespace from one library is used in the scope of another library. import 'dart:html'; The only required argument to import is a URI specifying the library. For built-in libraries, the URI has the special dart: scheme. For other libraries, you can use a file system p...

Unlike Java, Dart doesn’t have the keywords public, protected, and private. If an identifier starts with an underscore _, it’s private to its library. If you for example have class A in a separate library file (eg, other.dart), such as: library other; class A { int _private = 0; testA()...