Tutorial by Examples: ga

Functions are only useful if we can call them. To call a function the following syntax is used: print("Hello, World!") We're calling the print function. Using the argument "Hello, World". As is obvious, this will print Hello, World to the output stream. The returned value is ...

Functions in Common Lisp are first class values. An anonymous function can be created by using lambda. For example, here is a function of 3 arguments which we then call using funcall CL-USER> (lambda (a b c) (+ a (* b c))) #<FUNCTION (LAMBDA (A B C)) {10034F484B}> CL-USER> (defvar *fo...

Agents can be added to a JVM at runtime. To load an agent you will need to use the Attach API's VirtualMachine.attatch(String id). You can then load a compiled agent jar with the following method: public static void loadAgent(String agentPath) { String vmName = ManagementFactory.getRuntimeMXBe...

Generally speaking, empty commits (or commits with state that is identical to the parent) is an error. However, when testing build hooks, CI systems, and other systems that trigger off a commit, it's handy to be able to easily create commits without having to edit/touch a dummy file. The --allow-e...

The .sort() method sorts the elements of an array. The default method will sort the array according to string Unicode code points. To sort an array numerically the .sort() method needs to have a compareFunction passed to it. Note: The .sort() method is impure. .sort() will sort the array in-place...

// View to hold the CAGradientLayer. let view: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 320)) // Initialize gradient layer. let gradientLayer: CAGradientLayer = CAGradientLayer() // Set frame of gradient layer. gradientLayer.frame = view.bounds // Color a...

// View to hold the CAGradientLayer. let view: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 320)) // Initialize gradient layer. let gradientLayer: CAGradientLayer = CAGradientLayer() // Set frame of gradient layer. gradientLayer.frame = view.bounds // Color at the top of...

// View to hold the CAGradientLayer. let view: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 320)) // Initialize gradient layer. let gradientLayer: CAGradientLayer = CAGradientLayer() // Set frame of gradient layer. gradientLayer.frame = view.bounds // Color at the top of...

Constructor functions are functions designed to construct a new object. Within a constructor function, the keyword this refers to a newly created object which values can be assigned to. Constructor functions "return" this new object automatically. function Cat(name) { this.name = name;...

Forms can be defined, in a similar manner to models, by subclassing django.forms.Form. Various field input options are available such as CharField, URLField, IntegerField, etc. Defining a simple contact form can be seen below: from django import forms class ContactForm(forms.Form): contac...

In the Web App blade of the Azure Portal, click All settings > WebJobs to show the WebJobs blade: Click Add. The Add WebJob dialog appears. Under Name, provide a name for the WebJob. The name must start with a letter or a number and cannot contain any special characters other than...

Model creation Model classes must extend Illuminate\Database\Eloquent\Model. The default location for models is the /app directory. A model class can be easily generated by the Artisan command: php artisan make:model [ModelName] This will create a new PHP file in app/ by default, which is name...

EXPOSE <port> [<port>...] From Docker's documentation: The EXPOSE instruction informs Docker that the container listens on the specified network ports at runtime. EXPOSE does not make the ports of the container accessible to the host. To do that, you must use either the -p flag to ...

It is possible to mount a host directory to a specific path in your container using the -v or --volume command line option. The following example will mount /etc on the host to /mnt/etc in the container: (on linux) docker run -v "/etc:/mnt/etc" alpine cat /mnt/etc/passwd (on windows) do...

Before Python 3.5+ was released, the asyncio module used generators to mimic asynchronous calls and thus had a different syntax than the current Python 3.5 release. Python 3.x3.5 Python 3.5 introduced the async and await keywords. Note the lack of parentheses around the await func() call. import ...

By default, containers created with docker run are given a random hostname. You can give the container a different hostname by passing the --hostname flag: docker run --hostname redbox -d ubuntu:14.04

There are two ways to achieve that, the first and most known is the following: docker attach --sig-proxy=false <container> This one literally attaches your bash to the container bash, meaning that if you have a running script, you will see the result. To detach, just type: Ctl-P Ctl-Q Bu...

Sometimes you need rewrite history with a rebase, but git push complains about doing so because you rewrote history. This can be solved with a git push --force, but consider git push --force-with-lease, indicating that you want the push to fail if the local remote-tracking branch differs from the b...

Sometimes, you need to work with an array while ensuring you don't modify the original. Instead of a clone method, arrays have a slice method that lets you perform a shallow copy of any part of an array. Keep in mind that this only clones the first level. This works well with primitive types, like n...

Header file UIColor+XYZPalette.h: @interface UIColor (XYZPalette) +(UIColor *)xyz_indigoColor; @end and implementation UIColor+XYZPalette.m: @implementation UIColor (XYZPalette) +(UIColor *)xyz_indigoColor { return [UIColor colorWithRed:75/255.0f green:0/255.0f blue:130/255.0f al...