Tutorial by Examples: re

The size of a canvas is the area it occupies on the page and is defined by the CSS width and height properties. canvas { width : 1000px; height : 1000px; } The canvas resolution defines the number of pixels it contains. The resolution is set by setting the canvas element width and heigh...

Starter code to create and remove a full page canvas that responds to resize events via javascript. var canvas; // Global canvas reference var ctx; // Global 2D context reference // Creates a canvas function createCanvas () { const canvas = document.createElement(&q...

Many times when working with the canvas you will need to have a canvas to hold some intrum pixel data. It is easy to create an offscreen canvas, obtain a 2D context. An offscreen canvas will also use the available graphics hardware to render. The following code simply creates a canvas and fills it ...

This example will show you how to create a simple animation using the canvas and the 2D context. It is assumed you know how to create and add a canvas to the DOM and obtain the context // this example assumes ctx and canvas have been created const textToDisplay = "This is an example that uses...

psql < backup.sql A safer alternative uses -1 to wrap the restore in a transaction. The -f specifies the filename rather than using shell redirection. psql -1f backup.sql Custom format files must be restored using pg_restore with the -d option to specify the database: pg_restore -d DATABA...

For each environment you need to create a separate appsettings.{EnvironmentName}.json files: appsettings.Development.json appsettings.Staging.json appsettings.Production.json Then open project.json file and include them into "include" in "publishOptions" section. This lis...

Redirect any naked domain to www.[your_domain].tld: # Start Apache Rewriting engine RewriteEngine On # Make sure you're not already using www subdomain # and that the host string is not empty RewriteCond %{HTTP_HOST} !^$ RewriteCond %{HTTP_HOST} !^www\. # We check for http/https connection ...

XML pre-defines five general entities that can be used without declaring them: & " ' < > They are associated with the names amp, quot, apos, lt and gt. <?xml version="1.0"?> <entities> & is an ampersand. " is a quote. ' is...

Bash indirection permits to get the value of a variable whose name is contained in another variable. Variables example: $ red="the color red" $ green="the color green" $ color=red $ echo "${!color}" the color red $ color=green $ echo "${!color}" the ...

1. URLByDeletingPathExtension: If the receiver represents the root path, this property contains a copy of the original URL. If the URL has multiple path extensions, only the last one is removed. 2. URLByAppendingPathExtension: Returns a new URL made by appending a path extension to the original U...

The figure contains all the plot elements. The main way to create a figure in matplotlib is to use pyplot. import matplotlib.pyplot as plt fig = plt.figure() You can optionally supply a number, which you can use to access a previously-created figure. If a number is not supplied, the last-create...

To create a JAR containing all of its dependencies, it is possible to use the built-in descriptor format jar-with-dependencies. The following example configures an execution of the Assembly Plugin bound to the package phase, using this built-in descriptor and declaring a main class of com.example: ...

First match: $ a='I am a string' $ echo "${a/a/A}" I Am a string All matches: $ echo "${a//a/A}" I Am A string Match at the beginning: $ echo "${a/#I/y}" y am a string Match at the end: $ echo "${a/%g/N}" I am a strinN Replace a pattern wi...

Project Object Model is the basic unit of Maven and defines the project structure, dependencies, etc. The following are very minimal to create a POM: project root modelVersion – should be set to 4.0.0 groupId – the ID of the project's group artifactId – the ID of the artifact (project) versi...

The modules of a multi-module project are aggregated from a hierarchical structure. The root pom packing should look like: <packaging>pom</packaging> The following will be the directory structure of the project: |-- sample-app \ `-- pom.xml |-- sample-module-1 | `--...

Commands have one input (STDIN) and two kinds of outputs, standard output (STDOUT) and standard error (STDERR). For example: STDIN root@server~# read Type some text here Standard input is used to provide input to a program. (Here we're using the read builtin to read a line from STDIN.) STDO...

{ echo "contents of home directory" ls ~ } > output.txt

It is possible to effectively apply a function (cb) which returns a promise to each element of an array, with each element waiting to be processed until the previous element is processed. function promiseForEach(arr, cb) { var i = 0; var nextPromise = function () { if (i >= arr.leng...

import pandas as pd df = pd.DataFrame({'gender': ["male", "female","female"], 'id': [1, 2, 3] }) >>> df gender id 0 male 1 1 female 2 2 female 3 To encode the male to 0 and female to 1: df.loc[df["gender&quot...

Ring is de-facto standard API for clojure HTTP applications, similar to Ruby's Rack and Python's WSGI. We're going to use it with http-kit webserver. Create new Leiningen project: lein new app myapp Add http-kit dependency to project.clj: :dependencies [[org.clojure/clojure "1.8.0&quot...