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F# allows functions to be added as "members" to types when they are defined (for example, Record Types). However F# also allows new instance members to be added to existing types - even ones declared elsewhere and in other .net languages. The following example adds a new instance method D...

F# allow existing types to be extended with new static functions. type System.String with static member EqualsCaseInsensitive (a, b) = String.Equals(a, b, StringComparison.OrdinalIgnoreCase) This new function can be invoked like this: let x = String.EqualsCaseInsensitive("abc", &...

Modules can be used to add new functions to existing Modules and Types. namespace FSharp.Collections module List = let pair item1 item2 = [ item1; item2 ] The new function can then be called as if it was an original member of List. open FSharp.Collections module Testing = le...

Download and install Xamarin Studio Community. Open Xamarin Studio. Click File → New → Solution. Click .NET → Console Project and choose C#. Click Next to proceed. Enter the Project Name and Browse... for a Location to Save and then click Create. The newly created project w...

Fix takes a "template" type and ties the recursive knot, layering the template like a lasagne. newtype Fix f = Fix { unFix :: f (Fix f) } Inside a Fix f we find a layer of the template f. To fill in f's parameter, Fix f plugs in itself. So when you look inside the template f you find a...

import os, sys from openpyxl import Workbook from datetime import datetime dt = datetime.now() list_values = [["01/01/2016", "05:00:00", 3], \ ["01/02/2016", "06:00:00", 4], \ ["01/03/2016", "07:00:00",...

OpenPyXL is a module for manipulating and creating xlsx/xlsm/xltx/xltm workbooks in memory. Manipulating and reading an existing workbook: import openpyxl as opx #To change an existing wookbook we located it by referencing its path workbook = opx.load_workbook(workbook_path) load_workbook() c...

Cryptography is something very hard and after spending a lot of time reading different examples and seeing how easy it is to introduce some form of vulnerability I found an answer originally written by @jbtule that I think is very good. Enjoy reading: "The general best practice for symmetric e...

Batch execution using java.sql.Statement allows you to execute multiple DML statements (update, insert, delete) at once. This is achieved by creating a single statement object, adding the statements to execute, and then execute the batch as one. Connection connection = ...; // obtained earlier c...

Compare the definition of Free to that of Fix: data Free f a = Return a | Free (f (Free f a)) newtype Fix f = Fix { unFix :: f (Fix f) } In particular, compare the type of the Free constructor with the type of the Fix constructor. Free layers up a functor just like Fix, except ...

Throughout this example it is assumed that the 'root' object that is being serialized to JSON is an instance of the following class : public class MyJson { }   Example 1 : An example of an instance of MyJson, as is: {} i.e. since the class has no fields, only curly brackets are serialized...

This is a script saved as .Rmd, on the contrary of r scripts saved as .R. To knit the script, either use the render function or use the shortcut button in Rstudio. --- title: "Rstudio exemple of a rmd file" author: 'stack user' date: "22 July 2016" output: html_document -...

C-style bit-manipulation // Bit n will be set if x is 1 and cleared if x is 0. number ^= (-x ^ number) & (1LL << n); Using std::bitset set(n,val) - sets bit n to the value val. std::bitset<5> num(std::string("00100")); num.set(0,true); // num is now 00101 num.set(...

// Example of std::vector as an expanding dynamic size array. #include <algorithm> // std::sort #include <iostream> #include <vector> // std::vector using namespace std; int int_from( std::istream& in ) { int x = 0; in >> x; return x; } ...

// A fixed size raw array matrix (that is, a 2D raw array). #include <iostream> #include <iomanip> using namespace std; auto main() -> int { int const n_rows = 3; int const n_cols = 7; int const m[n_rows][n_cols] = // A raw array matrix. ...

Unfortunately as of C++14 there's no dynamic size matrix class in the C++ standard library. Matrix classes that support dynamic size are however available from a number of 3rd party libraries, including the Boost Matrix library (a sub-library within the Boost library). If you don't want a dependenc...

Will select records in TableName that have records matching in TableName1. SELECT * FROM TableName t WHERE EXISTS ( SELECT 1 FROM TableName1 t1 where t.Id = t1.Id)

LISP and Scheme's greatest advantage over other mainstream programming language is their macro system. Unlike the C preprocessor and other macro languages, Scheme macros take parsed code as input and return expanded code as output. This is one of the applications of Scheme's “code is data” phrase, a...

<svg xmlns="http://www.w3.org/2000/svg"> <text x="40" y="60" font-size="28">Hello World!</text> </svg> The x and y coordinate specifies the position of the bottom-left corner of the text (unless text-anchor has been modified). ...

The rotate property rotates each character by the specified angle. <svg xmlns="http://www.w3.org/2000/svg"> <text x="10" y="20" rotate="30">Each character is rotated</text> </svg> To rotate the whole text element, you have to ...