Tutorial by Examples: w

Mixin with variable argument

There are some cases in mixins where there can be single or multiple arguments while using it. Let's take a case of border-radius where there can be single argument like border-radius:4px; or multiple arguments like border-radius:4px 3px 2px 1px;. Traditional with Keyword Arguments mixing will be l...

sass • Mixins

Building with SCons

You can build the cross-platform "Hello World" C++ code, using Scons - A Python-language software construction tool. First, create a file called SConstruct (note that SCons will look for a file with this exact name by default). For now, the file should be in a directory right along your h...

C++ • Build Systems

Message Propagation with Singleton Class

Instances never contain a method they only carry data. However we can define a singleton class for any object including an instance of a class. When a message is passed to an object (method is called) Ruby first checks if a singleton class is defined for that object and if it can reply to that mess...

Ruby Language • Singleton Class

Product collection - with attributes

//all attributes $collection = Mage::getModel('catalog/product') ->getCollection() ->addAttributeToSelect('*'); //specific attributes $collection = Mage::getModel('catalog/product') ->getCollection() ->addAttributeToSelect('name'); //certain attributes are special...

magento • Get Products from Database

Check if the product was correctly loaded

$productFound = ($product->getId() !== null)

magento • Get Products from Database

difference between two commit or branch

To view difference between two branch git diff <branch1>..<branch2> To view difference between two branch git diff <commitId1>..<commitId2> To view diff with current branch git diff <branch/commitId> To view summary of changes git diff --stat <branch/com...

Git • Git Diff

Using the revert command to discard unwanted changes.

The revert command allows discarding unwanted uncommitted changes. Reverting changes to a single file. hg revert example.c Reverting all changes. This will discard all changes not just the current directory. hg revert --all hg will output which files were reverted. reverting exa...

mercurial • Common operations

Use git send-email with Gmail

Background: if you work on a project like the Linux kernel, rather than make a pull request you will need to submit your commits to a listserv for review. This entry details how to use git-send email with Gmail. Add the following to your .gitconfig file: [sendemail] smtpserver = smtp.googlema...

Git • git send-email

When to use a Static variable

A Static variable declared locally is not destructed and does not lose its value when the Sub procedure is exited. Subsequent calls to the procedure do not require re-initialization or assignment although you may want to 'zero' any remembered value(s). These are particularly useful when late bindin...

VBA • Declaring Variables

Animate at a specified interval (add a new rectangle every 1 second)

This example adds a new rectangle to the canvas every 1 second (== a 1 second interval) Annotated Code: <!doctype html> <html> <head> <style> body{ background-color:white; } #canvas{border:1px solid red; } </style> <script> window.onload=(functio...

html5-canvas • Animation

Don't draw animations in your event handlers (a simple sketch app)

During mousemove you get flooded with 30 mouse events per second. You might not be able to redraw your drawings at 30 times per second. Even if you can, you're probably wasting computing power by drawing when the browser is not ready to draw (wasted == across display refresh cycles). Therefore it m...

html5-canvas • Animation

Download

A distribution can be downloaded from the Apache Struts website. The full distribution contains: the struts2-core.jar file related dependencies example applications a copy of the documentation in HTML format the complete source code. Blank Application The blank web application in the dis...

struts2 • Getting started with struts2

Working with Varargs parameters

Using varargs as a parameter for a method definition, it is possible to pass either an array or a sequence of arguments. If a sequence of arguments are passed, they are converted into an array automatically. This example shows both an array and a sequence of arguments being passed into the printVar...

Java Language • Varargs (Variable Argument)

Drawing images

Images can be drawn onto a JComponent using the drawImage method of class Graphics: loading an image BufferedImage img; try { img = ImageIO.read(new File("stackoverflow.jpg")); } catch (IOException e) { throw new RuntimeException("Could not load image", e); } dr...

swing • Graphics

Make text shorter but don't break last word

To make long text at most N characters long but leave last word intact, use .{0,N}\b pattern: ^(.{0,N})\b.*

Regular Expressions • Word Boundary

Master and Detail View interaction using Delegates in Objective C

UISplitViewController must be the rootViewController of your application. AppDelegate.m - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. self.window = [[UIWindow alloc] i...

iOS • UISplitViewController

Hello, World! (minimal)

Let's test our basic knowledge of tkinter by creating the classic "Hello, World!" program. First, we must import tkinter, this will vary based on version (see remarks section about "Differences between Python 2 and 3") In Python 3 the module tkinter has a lowercase t: import t...

tkinter • Getting started with tkinter

Hello, World! (modular, object-oriented)

import tkinter as tk class HelloWorld(tk.Frame): def __init__(self, parent): super(HelloWorld, self).__init__(parent) self.label = tk.Label(self, text="Hello, World!") self.label.pack(padx=20, pady=20) if __name__ == "__main__": ...

tkinter • Getting started with tkinter

Removing unwanted characters from a string

The example Checking a string for unwanted characters, describes how to test and reject strings that don't meet certain criteria. Obviously, rejecting input outright is not always possible, and sometimes you just have to make do with what you receive. In these cases, a cautious developer will attemp...

guava • Strings

Choosing Assertions Within Unittests

While Python has an assert statement, the Python unit testing framework has better assertions specialized for tests: they are more informative on failures, and do not depend on the execution's debug mode. Perhaps the simplest assertion is assertTrue, which can be used like this: import unittest ...

Python Language • Unit Testing