Tutorial by Examples: b

Swift's C interoperability allows you to use functions and types from the C standard library. On Linux, the C standard library is exposed via the Glibc module; on Apple platforms it's called Darwin. #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS) import Darwin #elseif os(Linux) import Glibc...

6 var myIterableObject = {}; // An Iterable object must define a method located at the Symbol.iterator key: myIterableObject[Symbol.iterator] = function () { // The iterator should return an Iterator object return { // The Iterator object must implement a method, next() next: func...

dynamic foo = 123; Console.WriteLine(foo + 234); // 357 Console.WriteLine(foo.ToUpper()) // RuntimeBinderException, since int doesn't have a ToUpper method foo = "123"; Console.WriteLine(foo + 234); // 123234 Console.WriteLine(foo.ToUpper()): // NOW A STRING

using System; using System.Dynamic; dynamic info = new ExpandoObject(); info.Id = 123; info.Another = 456; Console.WriteLine(info.Another); // 456 Console.WriteLine(info.DoesntExist); // Throws RuntimeBinderException

You can use a colon and the standard numeric format syntax to control how numbers are formatted. var decimalValue = 120.5; var asCurrency = $"It costs {decimalValue:C}"; // String value is "It costs $120.50" (depending on your local currency settings) var withThreeDecimal...

You can see what "hunks" of work would be staged for commit using the patch flag: git add -p or git add --patch This opens an interactive prompt that allows you to look at the diffs and let you decide whether you want to include them or not. Stage this hunk [y,n,q,a,d,/,s,e,?]? ...

arc4random_uniform(someNumber: UInt32) -> UInt32 This gives you random integers in the range 0 to someNumber - 1. The maximum value for UInt32 is 4,294,967,295 (that is, 2^32 - 1). Examples: Coin flip let flip = arc4random_uniform(2) // 0 or 1 Dice roll let roll = arc4random_...

What is Serialization Serialization is the process of converting an object's state (including its references) to a sequence of bytes, as well as the process of rebuilding those bytes into a live object at some future time. Serialization is used when you want to persist the object. It is also used b...

toList flattens a Foldable structure t a into a list of as. ghci> toList [7, 2, 9] -- t ~ [] [7, 2, 9] ghci> toList (Right 'a') -- t ~ Either e "a" ghci> toList (Left "foo") -- t ~ Either String [] ghci> toList (3, True) -- t ~ (,) Int [True] toList is ...

When json_encode or json_decode fails to parse the string provided, it will return false. PHP itself will not raise any errors or warnings when this happens, the onus is on the user to use the json_last_error() and json_last_error_msg() functions to check if an error occurred and act accordingly in ...

Mark your UIView subclass as an accessible element so that it is visible to VoiceOver. myView.isAccessibilityElement = YES; Ensure that the view speaks a meaningful label, value, and hint. Apple provides more details on how to choose good descriptions in the Accessibility Programming Guide.

The accessibility frame is used by VoiceOver for hit testing touches, drawing the VoiceOver cursor, and calculating where in the focused element to simulate a tap when the user double-taps the screen. Note that the frame is in screen coordinates! myElement.accessibilityFrame = frameInScreenCoordina...

VoiceOver can navigate many apps on iOS because most UIKit classes implement UIAccessibilityProtocol. Features that don’t represent onscreen elements using UIView, including apps that leverage Core Graphics or Metal to perform drawing, must describe these elements for accessibility. As of iOS 8.0, t...

1.8 You can remove a submodule (e.g. the_submodule) by calling: $ git submodule deinit the_submodule $ git rm the_submodule git submodule deinit the_submodule deletes the_submodules' entry from .git/config. This excludes the_submodule from git submodule update, git submodule sync and git ...

You can use a template in a function based view as follows: from django.shortcuts import render def view(request): return render(request, "template.html") If you want to use template variables, you can do so as follows: from django.shortcuts import render def view(request):...

Here is an init.d script for Bosun that includes setting Environmental Variables that can be used to hide secrets from the raw config. It uses http://software.clapper.org/daemonize/ to run the program as a daemon. #!/bin/sh # # /etc/rc.d/init.d/bosun # bosun # # chkconfig: - 98 02 # descripti...

#Create Bosun unit file at /etc/systemd/system/bosun.service [Unit] Description=Bosun Service After=network.target After=rsyslog.service [Service] Type=simple User=root ExecStart=/opt/bosun/bosun -c /opt/bosun/config/prod.conf Restart=on-abort [Install] WantedBy=multi-user.target #...

TSDBRelay can be used to forward metrics to an OpenTSDB instance, send to Bosun for indexing, and relay to another opentsdb compatible instance for backup/DR/HA. It also has options to denormalize metrics with high tag cardinality or create redis/ledis backed external counters. #Create tsdbrelay un...

Chef Scollector Cookbook: https://github.com/alexmbird/chef-scollector Chef Bosun Cookbook: https://github.com/ptqa/chef-bosun Puppet scollector module: https://github.com/axibase/axibase-puppet-modules Bosun Ansible/Vagrant example: https://github.com/gnosek/bosun-deploy

git bisect allows you to find which commit introduced a bug using a binary search. Start by bisecting a session by providing two commit references: a good commit before the bug, and a bad commit after the bug. Generally, the bad commit is HEAD. # start the git bisect session $ git bisect start ...