Tutorial by Examples: s

This program uses the Windows API (WinAPI) to print "Hello World" into a message box. To include a dependency (like Windows in this case), add the uses block including a comma-separated list of units ending with an semicolon. program HelloWorld; uses Windows; begin MessageBox...

A single case discriminated union is like any other discriminated union except that it only has one case. // Define single-case discriminated union type. type OrderId = OrderId of int // Construct OrderId type. let order = OrderId 123 // Deconstruct using pattern matching. // Parentheses used...

To document a function, it is often helpful to have an example script which uses your function. The publish function in Matlab can then be used to generate a help file with embedded pictures, code, links, etc. The syntax for documenting your code can be found here. The Function This function uses ...

There are seven different column types that can be used within a GridView. <asp:GridView ID="GridView1" runat="server"> <Columns> ... </Columns> </asp:GridView> BoundField: <asp:BoundField DataField="EmployeeID" Heade...

Folds are (higher-order) functions used with sequences of elements. They collapse seq<'a> into 'b where 'b is any type (possibly still 'a). This is a bit abstract so lets get into concrete practical examples. Calculating the sum of all numbers In this example, 'a is an int. We have a list of...

let x = true match x with | true -> printfn "x is true" yields a warning C:\Program Files (x86)\Microsoft VS Code\Untitled-1(2,7): warning FS0025: Incomplete pattern matches on this expression. For example, the value 'false' may indicate a case not covered by the pattern(s). ...

Incorrect usage: In the following snippet, the last match will never be used: let x = 4 match x with | 1 -> printfn "x is 1" | _ -> printfn "x is anything that wasn't listed above" | 4 -> printfn "x is 4" prints x is anything that wasn't listed abov...

type Person = { Age : int PassedDriversTest : bool } let someone = { Age = 19; PassedDriversTest = true } match someone.PassedDriversTest with | true when someone.Age >= 16 -> printfn "congrats" | true -> printfn "wait until you are 16" | false -> p...

>>> code = """for i in range(5):\n print('Hello world!')""" >>> exec(code) Hello world! Hello world! Hello world! Hello world! Hello world!

>>> expression = '5 + 3 * a' >>> a = 5 >>> result = eval(expression) >>> result 20

compile built-in function can be used to precompile an expression to a code object; this code object can then be passed to eval. This will speed up the repeated executions of the evaluated code. The 3rd parameter to compile needs to be the string 'eval'. >>> code = compile('a * b + c', '&l...

>>> variables = {'a': 6, 'b': 7} >>> eval('a * b', globals=variables) 42 As a plus, with this the code cannot accidentally refer to the names defined outside: >>> eval('variables') {'a': 6, 'b': 7} >>> eval('variables', globals=variables) Traceback (most ...

You can fetch the current properties of the Annotation by using Reflection to fetch the Method or Field or Class which has an Annotation applied to it, and then fetching the desired properties. @Retention(RetentionPolicy.RUNTIME) @interface MyAnnotation { String key() default "foo";...

As the static keyword is used for accessing fields and methods without an instantiated class, it can be used to declare constants for use in other classes. These variables will remain constant across every instantiation of the class. By convention, static variables are always ALL_CAPS and use unders...

Static gives a method or variable storage that is not allocated for each instance of the class. Rather, the static variable is shared among all class members. Incidentally, trying to treat the static variable like a member of the class instance will result in a warning: public class Apple { pu...

Jagged arrays are arrays that instead of primitive types, contain arrays (or other collections). It's like an array of arrays - each array element contains another array. They are similar to multidimensional arrays, but have a slight difference - as multidimensional arrays are limited to a fixed nu...

The Implement directive indicates that the web page, master page or user control page must implement the specified .Net framework interface. The basic syntax for implements directive is: <%@ Implements Interface="interface_name" %>

The Master directive specifies a page file as being the mater page. The basic syntax of sample MasterPage directive is: <%@ MasterPage Language="C#" AutoEventWireup="true" CodeFile="SiteMater.master.cs" Inherits="SiteMaster" %>

The MasterType directive assigns a class name to the Master property of a page, to make it strongly typed. The basic syntax of MasterType directive is: <%@ MasterType attribute="value"[attribute="value" ...] %>

This example show how you can check if a service already exists (i.e., is installed on the machine) or not. This code requires only the lowest privileges necessary, so each process can perform the check, no matter what level of security it is running at. #define UNICODE #define _UNICODE #include ...