Tutorial by Examples: n

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

Uppercase and Lowercase Strings

To make all the characters in a String uppercase or lowercase: 2.2 let text = "AaBbCc" let uppercase = text.uppercaseString // "AABBCC" let lowercase = text.lowercaseString // "aabbcc" 3.0 let text = "AaBbCc" let uppercase = text.uppercased() // &qu...

Swift Language • Strings and Characters

Installation or Setup

Basic installation: You can download redux javascript file, using this link. Also you can install redux, using bower : bower install https://npmcdn.com/redux@latest/dist/redux.min.js Next, you need to include redux to your page: <html> <head> <script type="text/jav...

redux • Getting started with redux

Filtering an array

In order to filter out values from an array and obtain a new array containing all the values that satisfy the filter condition, you can use the array_filter function. Filtering non-empty values The simplest case of filtering is to remove all "empty" values: $my_array = [1,0,2,null,3,'',...

PHP • Manipulating an Array

Product collection - LIKE query

$collection = Mage::getModel('catalog/product')->getCollection(); $collection->addAttributeToFilter('sku', array('like' => 'UX%'));

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

Matching on an Option

If you are matching on an Option type: def f(x: Option[Int]) = x match { case Some(i) => doSomething(i) case None => doSomethingIfNone } This is functionally equivalent to using fold, or map/getOrElse: def g(x: Option[Int]) = x.fold(doSomethingIfNone)(doSomething) def h(x: ...

Scala Language • Pattern Matching

Enqueuing scripts in functions.php

If you want to add custom.js script that is located in the js/ folder of your theme, you'll need to enqueue it. In functions.php add <?php add_action( 'after_setup_theme', 'yourtheme_theme_setup' ); if ( ! function_exists( 'yourtheme_theme_setup' ) ) { function yourtheme_theme_setup()...

WordPress • Enqueuing scripts

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

Select columns which are named after reserved keywords

When a column name matches a reserved keyword, standard SQL requires that you enclose it in double quotation marks: SELECT "ORDER", ID FROM ORDERS Note that it makes the column name case-sensitive. Some DBMSes have proprietary ways of quoting names. For example, SQL Serve...

SQL • SELECT

Grouping in ListView

asp:ListView introduced in ASP.NET WebForms framework 3.5 is the most flexible of all DataPresentation Controls in the framework. An example of Grouping using ListView (which will come handy as an image gallery) Objective: To display three images in a row using asp:ListView Markup <asp:ListVie...

ASP.NET • WebForms

Convenience functions to manipulate data.frames

Some convenience functions to manipulate data.frames are subset(), transform(), with() and within(). subset The subset() function allows you to subset a data.frame in a more convenient way (subset also works with other classes): subset(mtcars, subset = cyl == 6, select = c("mpg", "...

R Language • Data frames

DELETE certain rows with WHERE

This will delete all rows that match the WHERE criteria. DELETE FROM Employees WHERE FName = 'John'

SQL • DELETE

User Input

In Python 2, user input is accepted using the raw_input function, Python 2.x2.3 user_input = raw_input() While in Python 3 user input is accepted using the input function. Python 3.x3.0 user_input = input() In Python 2, the input function will accept input and interpret it. While this ...

Python Language • Incompatibilities moving from Python 2 to Python 3

Function syntax

Functions can be written using several types of syntax function name() integer name name = 42 end function integer function name() name = 42 end function function name() result(res) integer res res = 42 end function Functions return values through a function result....

Fortran • Procedures - Functions and Subroutines

ALWAYS Use "Option Explicit"

In the VBA Editor window, from the Tools menu select "Options": Then in the "Editor" tab, make sure that "Require Variable Declaration" is checked: Selecting this option will automatically put Option Explicit at the top of every VBA module. Small note: This is ...

excel-vba • VBA Best Practices

Pattern Matching Sealed Traits

When pattern matching an object whose type is a sealed trait, Scala will check at compile-time that all cases are 'exhaustively matched': sealed trait Shape case class Square(height: Int, width: Int) extends Shape case class Circle(radius: Int) extends Shape case object Point extends Shape ...

Scala Language • Pattern Matching

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

Escaping @ character

In many cases, the Razor parser is smart enough to figure out when the @ sign is meant to be used as part of code, as opposed to being part of something like an email address. In the example below, escaping the @ sign is not necessary: <p>Reach out to us at [email protected]</p> Howev...

asp.net-mvc • Razor

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