Tutorial by Examples: at

Retrieve Database Options

The following query returns the database options and metadata: select * from sys.databases WHERE name = 'MyDatabaseName';

Microsoft SQL Server • Retrieve information about the database

Convert string to float

parseFloat accepts a string as an argument which it converts to a float/ parseFloat("10.01") // = 10.01

JavaScript • Variable coercion/conversion

// Generic types are declared using the <T> annotation struct GenericType<T> { pub item: T } enum QualityChecked<T> { Excellent(T), Good(T), // enum fields can be generics too Mediocre { product: T } }

Rust • Generics

Instantiation

// explicit type declaration let some_value: Option<u32> = Some(13); // implicit type declaration let some_other_value = Some(66);

Rust • Generics

Creating a new object

PowerShell, unlike some other scripting languages, sends objects through the pipeline. What this means is that when you send data from one command to another, it's essential to be able to create, modify, and collect objects. Creating an object is simple. Most objects you create will be custom obj...

PowerShell • Working with Objects

Alternative loop syntax

You can also use loop with curly brackets like this: if ( have_posts() ) { while ( have_posts() ) { the_post(); var_dump( $post ); } }

WordPress • The Loop (main WordPress loop)

Calculate Content Bounds (for i.e. dynamic cell heights)

A common use case for wanting to calculate the frame a label will take up is for sizing table view cells appropriately. The recommended way of doing this is using the NSString method boundingRectWithSize:options:attributes:context:. options takes String drawing options: NSStringDrawingUsesLineFr...

iOS • UILabel

Complex Example - jQuery UI Dynamicly Create Dialog

Generally, dialog relies on a div within the HTML. Sometimes you may want to create a dialog from scratch, programmatically. Here is an example of a complex modal dialog created dynamically with interactive functions. HTML <div id="users-contain" class="ui-widget"> &lt...

jQuery UI Library • Dialog

Use requestAnimationFrame to fade in element

View jsFiddle: https://jsfiddle.net/HimmatChahal/jb5trg67/ Copy + Pasteable code below: <html> <body> <h1>This will fade in at 60 frames per second (or as close to possible as your hardware allows)</h1> <script> // Fad...

JavaScript • requestAnimationFrame

Member initialization

Each of the enum members may be initialized with a value. If a value is not specified for a member, by default it's initialized to 0 (if it's the first member in the member list) or to a value greater by 1 than the value of the preceding member. Module Module1 Enum Size Small ...

Visual Basic .NET Language • Enum

The Flags attribute

With the <Flags> attribute, the enum becomes a set of flags. This attribute enables assigning multiple values to an enum variable. The members of a flags enum should be initialized with powers of 2 (1, 2, 4, 8...). Module Module1 <Flags> Enum Material Wood = 1 ...

Visual Basic .NET Language • Enum

Builder Pattern / C# / Fluent Interrface

public class Email { public string To { get; set; } public string From { get; set; } public string Subject { get; set; } public string Body { get; set; } } public class EmailBuilder { private readonly Email _email; public EmailBuilder() { _email = ...

Design patterns • Builder Pattern

Committing at a specific date

git commit -m 'Fix UI bug' --date 2016-07-01 The --date parameter sets the author date. This date will appear in the standard output of git log, for example. To force the commit date too: GIT_COMMITTER_DATE=2016-07-01 git commit -m 'Fix UI bug' --date 2016-07-01 The date parameter accepts t...

Git • Committing

Bitwise operators

Bitwise operators perform operations on bit values of data. These operators convert operands to signed 32-bit integers in two's complement. Conversion to 32-bit integers Numbers with more than 32 bits discard their most significant bits. For example, the following integer with more than 32 bits i...

JavaScript • Bitwise operators

No return statement for a function with a non-void return type

Omitting the return statement in a function which is has a return type that is not void is undefined behavior. int function() { // Missing return statement } int main() { function(); //Undefined Behavior } Most modern day compilers emit a warning at compile time for this kind o...

C++ • Undefined Behavior

Spreadsheet to dict of DataFrames

with pd.ExcelFile('path_to_file.xls) as xl: d = {sheet_name: xl.parse(sheet_name) for sheet_name in xl.sheet_names}

pandas • Pandas IO tools (reading and saving data sets)

Pattern matching on a map

%{username: username} = %{username: "John Doe", id: 1} # username == "John Doe" %{username: username, id: 2} = %{username: "John Doe", id: 1} ** (MatchError) no match of right hand side value: %{id: 1, username: "John Doe"}

Elixir Language • Pattern matching

Basic State

State in React components is essential to manage and communicate data in your application. It is represented as a JavaScript object and has component level scope, it can be thought of as the private data of your component. In the example below we are defining some initial state in the constructor f...

React • State in React

setState()

The primary way that you make UI updates to your React applications is through a call to the setState() function. This function will perform a shallow merge between the new state that you provide and the previous state, and will trigger a re-render of your component and all decedents. Parameters ...

React • State in React

Sorting sequence containers by overloaded less operator

If no ordering function is passed, std::sort will order the elements by calling operator< on pairs of elements, which must return a type contextually convertible to bool (or just bool). Basic types (integers, floats, pointers etc) have already build in comparison operators. We can overload this ...

C++ • Sorting