F# Basic Tutorial
F# Useful Resources
Selected Reading
- F# - Namespaces
- F# - Modules
- F# - Events
- F# - Interfaces
- F# - Inheritance
- F# - Operator Overloading
- F# - Structures
- F# - Classes
- F# - Exception Handling
- F# - Pattern Matching
- F# - Enumerations
- F# - Delegates
- F# - Generics
- F# - Basic I/O
- F# - Mutable Dictionary
- F# - Mutable Lists
- F# - Arrays
- F# - Mutable Data
- F# - Discriminated Unions
- F# - Maps
- F# - Sets
- F# - Sequences
- F# - Lists
- F# - Records
- F# - Tuples
- F# - Options
- F# - Strings
- F# - Functions
- F# - Loops
- F# - Decision Making
- F# - Operators
- F# - Variables
- F# - Data Types
- F# - Basic Syntax
- F# - Program Structure
- F# - Environment Setup
- F# - Overview
- F# - Home
F# Useful Resources
Selected Reading
- Who is Who
- Computer Glossary
- HR Interview Questions
- Effective Resume Writing
- Questions and Answers
- UPSC IAS Exams Notes
F# - Records
F# - Records
A record is similar to a tuple, however it contains named fields. For example,
type website =
{ title : string;
url : string }
Defining Record
A record is defined as a type using the type keyword, and the fields of the record are defined as a semicolon-separated pst.
Syntax for defining a record is −
type recordName =
{ [ fieldName : dataType ] + }
Creating a Record
You can create a record by specifying the record s fields. For example, let us create a website record named homepage −
let homepage = { Title = "TutorialsPoint"; Url = "www.tutorialspoint.com" }
The following examples will explain the concepts −
Example 1
This program defines a record type named website. Then it creates some records of type website and prints the records.
(* defining a record type named website *)
type website =
{ Title : string;
Url : string }
(* creating some records *)
let homepage = { Title = "TutorialsPoint"; Url = "www.tutorialspoint.com" }
let cpage = { Title = "Learn C"; Url = "www.tutorialspoint.com/cprogramming/index.htm" }
let fsharppage = { Title = "Learn F#"; Url = "www.tutorialspoint.com/fsharp/index.htm" }
let csharppage = { Title = "Learn C#"; Url = "www.tutorialspoint.com/csharp/index.htm" }
(*printing records *)
(printfn "Home Page: Title: %A
URL: %A") homepage.Title homepage.Url
(printfn "C Page: Title: %A
URL: %A") cpage.Title cpage.Url
(printfn "F# Page: Title: %A
URL: %A") fsharppage.Title fsharppage.Url
(printfn "C# Page: Title: %A
URL: %A") csharppage.Title csharppage.Url
When you compile and execute the program, it yields the following output −
Home Page: Title: "TutorialsPoint"
URL: "www.tutorialspoint.com"
C Page: Title: "Learn C"
URL: "www.tutorialspoint.com/cprogramming/index.htm"
F# Page: Title: "Learn F#"
URL: "www.tutorialspoint.com/fsharp/index.htm"
C# Page: Title: "Learn C#"
URL: "www.tutorialspoint.com/csharp/index.htm"
Example 2
type student =
{ Name : string;
ID : int;
RegistrationText : string;
IsRegistered : bool }
let getStudent name id =
{ Name = name; ID = id; RegistrationText = null; IsRegistered = false }
let registerStudent st =
{ st with
RegistrationText = "Registered";
IsRegistered = true }
let printStudent msg st =
printfn "%s: %A" msg st
let main() =
let preRegisteredStudent = getStudent "Zara" 10
let postRegisteredStudent = registerStudent preRegisteredStudent
printStudent "Before Registration: " preRegisteredStudent
printStudent "After Registration: " postRegisteredStudent
main()
When you compile and execute the program, it yields the following output −
Before Registration: : {Name = "Zara";
ID = 10;
RegistrationText = null;
IsRegistered = false;}
After Registration: : {Name = "Zara";
ID = 10;
RegistrationText = "Registered";
IsRegistered = true;}
Advertisements