Tutorial by Examples: p

Blocks as Method Parameters

- (void)methodWithBlock:(returnType (^)(paramType1, paramType2, ...))name;

Objective-C Language • Blocks

In order to compare the equality of custom classes, you can override == and != by defining __eq__ and __ne__ methods. You can also override __lt__ (<), __le__ (<=), __gt__ (>), and __ge__ (>). Note that you only need to override two comparison methods, and Python can handle the rest (== ...

Python Language • Comparisons

Nested output buffers

You can nest output buffers and fetch the level for them to provide different content using the ob_get_level() function. <?php $i = 1; $output = null; while( $i <= 5 ) { // Each loop, creates a new output buffering `level` ob_start(); print "Current nest level: &quo...

PHP • Output Buffering

Capturing the output buffer to re-use later

In this example, we have an array containing some data. We capture the output buffer in $items_li_html and use it twice in the page. <?php // Start capturing the output ob_start(); $items = ['Home', 'Blog', 'FAQ', 'Contact']; foreach($items as $item): // Note we're about to step &q...

PHP • Output Buffering

Running output buffer before any content

ob_start(); $user_count = 0; foreach( $users as $user ) { if( $user['access'] != 7 ) { continue; } ?> <li class="users user-<?php echo $user['id']; ?>"> <a href="<?php echo $user['link']; ?>"> <?php echo $user...

PHP • Output Buffering

Using Output buffer to store contents in a file, useful for reports, invoices etc

<?php ob_start(); ?> <html> <head> <title>Example invoice</title> </head> <body> <h1>Invoice #0000</h1> <h2>Cost: &pound;15,000</h2> ... </body> </html> <?php...

PHP • Output Buffering

Using the multiprocessing module to parallelise tasks

import multiprocessing def fib(n): """computing the Fibonacci in an inefficient way was chosen to slow down the CPU.""" if n <= 2: return 1 else: return fib(n-1)+fib(n-2) p = multiprocessing.Pool() print(p.map(fib,[38,37,3...

Python Language • Parallel computation

Ignore files that have already been committed to a Git repository

If you have already added a file to your Git repository and now want to stop tracking it (so that it won't be present in future commits), you can remove it from the index: git rm --cached <file> This will remove the file from the repository and prevent further changes from being tracked by...

Git • Ignoring Files and Folders

Recorded (not live) Video Player

twitch • Interactive Embed Video Player

Introduction to WordPress

WordPress [WP] is an open source Content Management System for building apps, websites, and blogs. WP is written in PHP and uses MySQL as the data store for the user content and configuration. It has a rich ecosystem of plugins and themes and enjoys a vibrant open source community, good documentatio...

WordPress • Getting started with WordPress

Limit and Offset relationship

Considering the following users table: idusername1User12User23User34User45User5 In order to constrain the number of rows in the result set of a SELECT query, the LIMIT clause can be used together with one or two positive integers as arguments (zero included). LIMIT clause with one argument When ...

MySQL • Limit and Offset

Simple Category

Interface and implementation of a simple category on NSArray, named Filter, with a single method that filters numbers. It is good practice to add a prefix (PF) to the method to ensure we don't overwrite any future NSArray methods. @interface NSArray (PFFilter) - (NSArray *)pf_filterSmaller:(dou...

Objective-C Language • Categories

General Pattern that does most commonly asked about tasks

The following is how to properly use the java.util.Scanner class to interactively read user input from System.in correctly( sometimes referred to as stdin, especially in C, C++ and other languages as well as in Unix and Linux). It idiomatically demonstrates the most common things that are requested ...

Java Language • Scanner

Getting the First Page in Ruby

This Ruby example uses Mechanize, a library to automate web interactions. client_id is an OAuth client_id. game is the game directory to list. require 'mechanize' master_agent = Mechanize.new client_id = "123" game = "Minecraft" url = "https://api.twitch.tv/kraken...

twitch • Lists of Streamers by Game

Start with a Muted Player

twitch • Interactive Embed Video Player

Implements Interface

This is an enum that is also a callable function that tests String inputs against precompiled regular expression patterns. import java.util.function.Predicate; import java.util.regex.Pattern; enum RegEx implements Predicate<String> { UPPER("[A-Z]+"), LOWER("[a-z]+&quot...

Java Language • Enums

Precondition and Postcondition

One use case for assertion is precondition and postcondition. This can be very useful to maintain invariant and design by contract. For a example a length is always zero or positive so this function must return a zero or positive value. #include <stdio.h> /* Uncomment to disable `assert()`...

C Language • Assertion

Making a Payment with a Vaulted Credit Card (Node)

In this example, we'll be looking at how to store a credit card using the PayPal vault, then reference that stored credit card to process a credit card transaction for a user. The reason why we would want to use the vault is so that we don't have to store sensitive credit card information on our ow...

PayPal • Making a Credit Card Payment (Node)

JavaScript/Web SDK

For JavaScript, here is the code we recommend for generating, persisting and retrieving a UUID. This could be wrapped in a function can called directly from the PUBNUB.init function rather than the two step inline solution below. // get/create/store UUID var UUID = PUBNUB.db.get('session') || (fun...

PubNub • UUIDs

Arithmetic operators

You can overload all basic arithmetic operators: + and += - and -= * and *= / and /= & and &= | and |= ^ and ^= >> and >>= << and <<= Overloading for all operators is the same. Scroll down for explanation Overloading outside of class/struct: //operator...

C++ • Operator Overloading