Tutorial by Examples: ch

trait HelloWorld { public function sayHello() { echo 'Hello World!'; } } // Change visibility of sayHello class MyClass1 { use HelloWorld { sayHello as protected; } } // Alias method with changed visibility // sayHello visibility not changed class MyClass2 { u...

A common task is to convert all columns of a data.frame to character class for ease of manipulation, such as in the cases of sending data.frames to a RDBMS or merging data.frames containing factors where levels may differ between input data.frames. The best time to do this is when the data is read ...

char literals are defined by wrapping the value with single-quotes ': char c = 'h'; Character literals may contain escape sequences. See String Escape Sequences A character literal must be exactly one character long (after all escape sequences have been evaluated). Empty character literals are ...

let rec factorial n = match n with | 0 | 1 -> 1 | n -> n * (factorial (n - 1)) This function matches on both the values 0 and 1 and maps them to the base case of our recursive definition. Then all other numbers map to the recursive call of this function.

The following assumes you will use kdiff3 for file diffing and although not essential it is a good idea. C:\> choco install kdiff3 Git can be installed first so you can state any parameters you wish. Here all the Unix tools are also installed and 'NoAutoCrlf' means checkout as is, commit as i...

Launch the Check In dialog for TFVS. $ git tfs checkintool This will take all of your local commits and create a single check-in.

This is a common gotcha with Laravel routes. Routes are matched in the order that they are declared. The first matching route is the one that is used. This example will work as expected: Route::get('/posts/{postId}/comments/{commentId}', 'CommentController@show'); Route::get('/posts/{postId}', 'P...

Meteor Tool To check the installed version of the Meteor tool, just run the following command outside of any Meteor projects: meteor --version To get a list of all official (recommended) Meteor releases, run: meteor show METEOR Meteor Projects If you want to check the project version of Me...

Machine code is term for the data in particular native machine format, which are directly processed by the machine - usually by the processor called CPU (Central Processing Unit). Common computer architecture (von Neumann architecture) consist of general purpose processor (CPU), general purpose mem...

Describes ranges of symbols You can enumerate symbols explicitly /[abc]/ # 'a' or 'b' or 'c' Or use ranges /[a-z]/ # from 'a' to 'z' It is possible to combine ranges and single symbols /[a-cz]/ # 'a' or 'b' or 'c' or 'z' Leading dash (-) is treated as charachter /[-a-c]/ # '-' or 'a' o...

ClientContext clientContext = new ClientContext(siteUrl); SP.List oList = clientContext.Web.Lists.GetByTitle("MyList"); int itemId = 2; ListItem oListItem = oList.Items.GetById(itemId); oListItem.BreakRoleInheritance(true); User oUser = clientContext.Web.SiteUsers.GetByLoginName...

The when-statement is an alternative to an if-statement with multiple else-if-branches: when { str.length == 0 -> print("The string is empty!") str.length > 5 -> print("The string is short!") else -> print("The string is long!") ...

When given an argument, the when-statement matches the argument against the branches in sequence. The matching is done using the == operator which performs null checks and compares the operands using the equals function. The first matching one will be executed. when (x) { "English" -...

(This pitfall applies equally to all primitive wrapper types, but we will illustrate it for Integer and int.) When working with Integer objects, it is tempting to use == to compare values, because that is what you would do with int values. And in some cases this will seem to work: Integer int1_1 =...

If you need to know whether a value's type extends or implements a given type, but you don't want to actually cast it as that type, you can use the is operator. if(value is int) { Console.WriteLine(value + "is an int"); }

Prerequisites The Windows version of Elasticsearch can be obtained from this link: https://www.elastic.co/downloads/elasticsearch. The latest stable release is always at the top. As we are installing on Windows, we need the .ZIP archive. Click the link in the Downloads: section and save the file t...

Type check: variable.isInstanceOf[Type] With pattern matching (not so useful in this form): variable match { case _: Type => true case _ => false } Both isInstanceOf and pattern matching are checking only the object's type, not its generic parameter (no type reification), except fo...

Often times you will want to have events for your objects. function spanOver(d,i){ var span = d3.select(this); span.classed("spanOver",true); } function spanOut(d,i){ var span = d3.select(this); span.classed("spanOver", false); } var div = d3.select('#divID')...

In development, you may find that using require() on the same module multiple times always returns the same module, even if you have made changes to that file. This is because modules are cached the first time they are loaded, and any subsequent module loads will load from the cache. To get around ...

Most modern distributions will come with BASH (Bourne Again SHell) pre-installed and configured as a default shell. The command (actually an executable binary, an ELF) that is responsible for changing shells in Linux is chsh (change shell). We can first check which shells are already installed and...