Tutorial by Examples: b

Execution of a JavaScript file in MongoDB

./mongo localhost:27017/mydb myjsfile.js Explanation: This operation executes the myjsfile.js script in a mongo shell that connects to the mydb database on the mongod instance accessible via the localhost interface on port 27017. localhost:27017 is not mandatory as this is the default port mongo...

MongoDB • Getting started with MongoDB

Basic API Usage

It can also be installed by downloading the source code and placing it in a directory of your project. However there are many benefits to using composer. require '/path/to/lib/Twig/Autoloader.php'; Twig_Autoloader::register(); $loader = new Twig_Loader_Filesystem('/path/to/templates'); $opti...

twig • Getting started with twig

Get product by sku

$sku = 'sku-goes-here'; $product = Mage::getModel('catalog/product')->loadByAttribute('sku', $sku);

magento • Get Products from Database

Get product by ID

$id = 1; $product = Mage::getModel('catalog/product')->load($id); if($product->getId()){ //product was found }

magento • Get Products from Database

Get product collection by attribute

$collection = Mage::getModel('catalog/product')->getCollection(); // Using operator $collection->addAttributeToFilter('status', array('eq' => 1)); // Without operator (automatically uses 'equal' operator $collection->addAttributeToFilter('status', 1);

magento • Get Products from Database

Basic creation of factors

Factors are one way to represent categorical variables in R. A factor is stored internally as a vector of integers. The unique elements of the supplied character vector are known as the levels of the factor. By default, if the levels are not supplied by the user, then R will generate the set of uniq...

R Language • Factors

Using split in the split-apply-combine paradigm

A popular form of data analysis is split-apply-combine, in which you split your data into groups, apply some sort of processing on each group, and then combine the results. Let's consider a data analysis where we want to obtain the two cars with the best miles per gallon (mpg) for each cylinder cou...

R Language • Split function

Use of bsxfun

Quite often, the reason why code has been written in a for loop is to compute values from 'nearby' ones. The function bsxfun can often be used to do this in a more succinct fashion. For example, assume that you wish to perform a columnwise operation on the matrix B, subtracting the mean of each col...

MATLAB Language • Vectorization

Database Files

Display all data files for all databases with size and growth info SELECT d.name AS 'Database', d.database_id, SF.fileid, SF.name AS 'LogicalFileName', CASE SF.status & 0x100000 WHEN 1048576 THEN 'Percentage' WHEN 0 THEN 'MB...

Microsoft SQL Server • Retrieve information about the database

Using BASE_DIR to ensure app portability

It's a bad idea to hard code paths in your application. One should always use relative urls so that your code can work seamlessly across different machines. The best way to set this up is to define a variable like this import os BASE_DIR = os.path.dirname(os.path.dirname(__file__)) Then use th...

Django • Settings

Using Environment variables to manage Settings across servers

Using environment variables is a widely used way to setting an app's config depending on it environment, as stated in The Twelve-Factor App. As configurations are likely to change between deployment environments, this is a very interesting way to modify the configuration without having to dig in th...

Django • Settings

Enum to string and back

public enum DayOfWeek { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday } // Enum to string string thursday = DayOfWeek.Thursday.ToString(); // "Thursday" string seventhDay = Enum.GetName(typeof(DayOfWeek), 6); // "Satur...

C# Language • Enum

Basic Template

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-widt...

twitter-bootstrap • Getting started with twitter-bootstrap

ThenBy

ThenBy can only be used after a OrderBy clause allowing to order using multiple criteria var persons = new[] { new {Id = 1, Name = "Foo", Order = 1}, new {Id = 1, Name = "FooTwo", Order = 2}, new {Id = 2, Name = "Bar", Order = 2}, new {Id = 2, Nam...

.NET Framework • LINQ

Background Shorthand

The background property can be used to set one or more background related properties: ValueDescriptionCSS Ver.background-imageBackground image to use1+background-colorBackground color to apply1+background-positionBackground image's position1+background-sizeBackground image's size3+background-repeat...

CSS • Backgrounds

Substring

Syntax is: SUBSTRING ( string_expression, start, length ). Note that SQL strings are 1-indexed. SELECT SUBSTRING('Hello', 1, 2) --returns 'He' SELECT SUBSTRING('Hello', 3, 3) --returns 'llo' This is often used in conjunction with the LEN() function to get the last n characters of a string of un...

SQL • String Functions

Using a Function Object Consumer

We can provide a consumer that will be called with the multiple relevant values: C++11 template <class F> void foo(int a, int b, F consumer) { consumer(a + b, a - b, a * b, a / b); } // use is simple... ignoring some results is possible as well foo(5, 12, [](int sum, int , int , i...

C++ • Returning several values from a function

Basic Discriminated Union Usage

Discriminated unions in F# offer a a way to define types which may hold any number of different data types. Their functionality is similar to C++ unions or VB variants, but with the additional benefit of being type safe. // define a discriminated union that can hold either a float or a string type...

F# • Discriminated Unions

Default values for instance variables

If the variable contains a value of an immutable type (e.g. a string) then it is okay to assign a default value like this class Rectangle(object): def __init__(self, width, height, color='blue'): self.width = width self.height = height self.color = color d...

Python Language • Classes

Numbers

In Erlang, numbers are either integers or floats. Erlang uses arbitrary-precision for integers (bignums), so their values are limited only by the memory size of your system. 1> 11. 11 2> -44. -44 3> 0.1. 0.1 4> 5.1e-3. 0.0051 5> 5.2e2. 520.0 Numbers can be used in various...

Erlang Language • Data Types