Tutorial by Examples: ar

Namespace variables

The variable command ensures that a given namespace variable is created. Until a value is assigned to it, the variable's value is undefined: namespace eval mynamespace { variable alpha set alpha 0 } The variable can be accessed from outside the namespace (from anywhere, in fact) by at...

tcl • Variables

Gradle Parallel builds

Gradle will only run one task at a time by default, regardless of the project structure. By using the --parallel switch, you can force Gradle to execute independent subprojects - those that have no implicit or explicit project dependencies between one another - in parallel, allowing it to run multip...

gradle • Gradle Performance

Ignoring return values of library functions

Almost every function in C standard library returns something on success, and something else on error. For example, malloc will return a pointer to the memory block allocated by the function on success, and, if the function failed to allocate the requested block of memory, a null pointer. So you sho...

C Language • Common pitfalls

Newline character is not consumed in typical scanf() call

When this program #include <stdio.h> #include <string.h> int main(void) { int num = 0; char str[128], *lf; scanf("%d", &num); fgets(str, sizeof(str), stdin); if ((lf = strchr(str, '\n')) != NULL) *lf = '\0'; printf("%d \"%s\&...

C Language • Common pitfalls

Minimal Chart Example

Depending on the version of Chart.JS you are using (the current one being 2.X), the syntax is different to create a minimal example of a bar chart (JSFiddle Demo for 2.X). Chart.js 2.X <html> <body> <canvas id="myChart" width="400" height="400&...

chart.js • Getting started with chart.js

Natural (comparable) vs explicit (comparator) sorting

There are two Collections.sort() methods: One that takes a List<T> as a parameter where T must implement Comparable and override the compareTo() method that determines sort order. One that takes a List and a Comparator as the arguments, where the Comparator determines the sort order. ...

Java Language • Comparable and Comparator

Creating an array of variables

$username = 'Hadibut'; $email = '[email protected]'; $variables = compact('username', 'email'); // $variables is now ['username' => 'Hadibut', 'email' => '[email protected]'] This method is often used in frameworks to pass an array of variables between two components.

PHP • Arrays

Compiled data bindings: The {x:Bind} markup extension

Databings are essential for working with XAML. The XAML dialect for UWP apps provides a type of binding: the {x:Bind} markup extension. Working with {Binding XXX} and {x:Bind XXX} is mostly equivalent, with the difference that the x:Bind extension works at compile time, which enables better debuggi...

xaml • Differences in the various XAML dialects

Show Toast Message Above Soft Keyboard

By default, Android will display Toast messages at the bottom of the screen even if the keyboard is showing. This will show a Toast message just above the keyboard. public void showMessage(final String message, final int length) { View root = findViewById(android.R.id.content); Toast toas...

Android • Toast

Rules for some of the widely used Libraries

Currently it contains rules for following libraries:- ButterKnife RxJava Android Support Library Android Design Support Library Retrofit Gson and Jackson Otto Crashlitycs Picasso Volley OkHttp3 Parcelable #Butterknife -keep class butterknife.** { *; } -keepnames class * { @butterk...

Android • ProGuard - Obfuscating and Shrinking your code

Enable ProGuard for your build

For enabling ProGuard configurations for your application you need to enable it in your module level gradle file. you need to set the value of minifyEnabled true. You can also enable shrinkResources true which will remove resources that ProGuard flaggs as unused. buildTypes { release { ...

Android • ProGuard - Obfuscating and Shrinking your code

Simple Thread without Arguments

This basic example counts at different rates on two threads that we name sync (main) and async (new thread). The main thread counts to 15 at 1Hz (1s) while the second counts to 10 at 0.5Hz (2s). Because the main thread finishes earlier, we use pthread_join to make it wait async to finish. #include ...

POSIX • Threads

Jagged Arrays (Arrays of Arrays)

Due to not being Excel-VBA exclusive contents this Example has been moved to VBA documentation. Link: Jagged Arrays (Arrays of Arrays)

excel-vba • Arrays

Creating a search form

To create a search form, enter the following code <%= form_tag("/search", method: "get") do %> <%= label_tag(:q, "Search for:") %> <%= text_field_tag(:q) %> <%= submit_tag("Search") %> <% end %> form_tag: This is t...

Ruby on Rails • Form Helpers

Resolving Implicit Parameters Using 'implicitly'

Assuming an implicit parameter list with more than one implicit parameter: case class Example(p1:String, p2:String)(implicit ctx1:SomeCtx1, ctx2:SomeCtx2) Now, assuming that one of the implicit instances is not available (SomeCtx1) while all other implicit instances needed are in-scope, to creat...

Scala Language • Implicits

Start using ES6/7 with Babel

Browser support for ES6 is growing, but to be sure your code will work on environments that dont fully support it, you can use Babel, the ES6/7 to ES5 transpiler, try it out! If you would like to use ES6/7 in your projects without having to worry about compatibility, you can use Node and Babel CLI ...

JavaScript • Transpiling

D3js with Angular

Using D3js with Angular can open up new fronts of possibilities such as live updation of charts as soon as data is updated. We can encapsulate complete chart functionality within an Angular directive, which makes it easily reusable. index.html >> <!DOCTYPE html> <html ng-app="...

d3.js • Using D3 with other frameworks

Start App

Using start option npm start Using Nodemon nodemon Using forever forever start 'js file name' To stop in forever forever stop ''js file name' To restart in forever forever restart 'js filename' List the server ruuning using forever forever list

express • express-generator

PARQUET

Parquet columnar storage format in Hive 0.13.0 and later. Parquet is built from the ground up with complex nested data structures in mind, and uses the record shredding and assembly algorithm described in the Dremel paper. We believe this approach is superior to simple flattening of nested name spac...

hive • File formats in HIVE

Arithmetic Operators

MySQL provides the following arithmetic operators OperatorNameExample+AdditionSELECT 3+5; -> 8 SELECT 3.5+2.5; -> 6.0 SELECT 3.5+2; -> 5.5-SubtractionSELECT 3-5; -> -2*MultiplicationSELECT 3 * 5; -> 15/DivisionSELECT 20 / 4; -> 5 SELECT 355 / 113; -> 3.1416 SELECT 10.0 / 0; -...

MySQL • Arithmetic