Tutorial by Examples: b

float float is an alias to the .NET datatype System.Single. It allows IEEE 754 single-precision floating point numbers to be stored. This data type is present in mscorlib.dll which is implicitly referenced by every C# project when you create them. Approximate range: -3.4 × 1038 to 3.4 × 1038 Deci...

Rails uses sqlite3 as the default database, but you can generate a new rails application with a database of your choice. Just add the -d option followed by the name of the database. $ rails new MyApp -T -d postgresql This is a (non-exhaustive) list of available database options: mysql oracle...

Suppose you have a repository structure like this: examples/ output.log src/ <files not shown> output.log README.md output.log in the examples directory is valid and required for the project to gather an understanding while the one beneath src/ is created while debugging a...

interface IFoo { } class Foo : IFoo { } class Bar : IFoo { } var item0 = new Foo(); var item1 = new Foo(); var item2 = new Bar(); var item3 = new Bar(); var collection = new IFoo[] { item0, item1, item2, item3 }; Using OfType var foos = collection.OfType<Foo>(); // result: IEnum...

Modules can have a special variable named __all__ to restrict what variables are imported when using from mymodule import *. Given the following module: # mymodule.py __all__ = ['imported_by_star'] imported_by_star = 42 not_imported_by_star = 21 Only imported_by_star is imported when usi...

The checked out file will overwrite not yet commited changes you did in this file. This command will check out the file file.example (which is located in the directory path/to/) and overwrite any changes you might have made to this file. git checkout some-branch path/to/file some-branch can be ...

There are two ways to connect to a MySQL/MariaDB server, depending on your infrastructure. Standard (TCP/IP) connection $dsn = 'mysql:dbname=demo;host=server;port=3306;charset=utf8'; $connection = new \PDO($dsn, $username, $password); // throw exceptions, when SQL error is caused $connection-...

To print a listing of the Error Code descriptions to the Immediate Window, pass it to the Debug.Print function: Private Sub ListErrCodes() Debug.Print "List Error Code Descriptions" For i = 0 To 65535 e = Error(i) If e <> "Application-defined or obje...

First, some terminology: argument (actual parameter): the actual variable being passed to a function; parameter (formal parameter): the receiving variable that is used in a function. In Python, arguments are passed by assignment (as opposed to other languages, where arguments can be passed by...

INSERT INTO `table_name` (`field_one`, `field_two`) VALUES ('value_one', 'value_two'); In this trivial example, table_name is where the data are to be added, field_one and field_two are fields to set data against, and value_one and value_two are the data to do against field_one and field_two resp...

Normally you would want to avoid using cursors as they can have negative impacts on performance. However in some special cases you may need to loop through your data record by record and perform some action. DECLARE @orderId AS INT -- here we are creating our cursor, as a local cursor and only a...

// You need a writable database to insert data final SQLiteDatabase database = openHelper.getWritableDatabase(); // Create a ContentValues instance which contains the data for each column // You do not need to specify a value for the PRIMARY KEY column. // Unique values for these are automatic...

A module is a file containing Python definitions and statements. Function is a piece of code which execute some logic. >>> pow(2,3) #8 To check the built in function in python we can use dir(). If called without an argument, return the names in the current scope. Else, return an alph...

Just execute lsb_release -a. On Debian: $ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux testing (stretch) Release: testing Codename: stretch On Ubuntu: $ lsb_release -a No LSB modules are available. Distributor ID: Ubun...

The most common way to create a Symbol object is by prefixing the string identifier with a colon: :a_symbol # => :a_symbol :a_symbol.class # => Symbol Here are some alternative ways to define a Symbol, in combination with a String literal: :"a_symbol" "a_symbol&quot...

Given a String: s = "something" there are several ways to convert it to a Symbol: s.to_sym # => :something :"#{s}" # => :something

Given a Symbol: s = :something The simplest way to convert it to a String is by using the Symbol#to_s method: s.to_s # => "something" Another way to do it is by using the Symbol#id2name method which is an alias for the Symbol#to_s method. But it's a method that is unique to the...

NSDictionary *inventory = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInt:13], @"Mercedes-Benz SLK250", [NSNumber numberWithInt:22], @"Mercedes-Benz E350", [NSNumber numberWithInt:19], @"BMW M3 Coupe", [NSNumber numberWithInt:16],...

Scope A variable can be declared (in increasing visibility level): At procedure level, using the Dim keyword in any procedure; a local variable. At module level, using the Private keyword in any type of module; a private field. At instance level, using the Friend keyword in any type of class m...

You can open the VB editor in any of the Microsoft Office applications by pressing Alt+F11 or going to the Developer tab and clicking on the "Visual Basic" button. If you don't see the Developer tab in the Ribbon, check if this is enabled. By default the Developer tab is disabled. To enab...