Using LINQ in F#

F# has query expressions that help to easily build Language Integrated Query (LINQ)  queries. Query expressions can be declared as query { ... }. It is a type of computation expression, just like the sequence expression. An example code is given as follows:

let data = [| 1..10 |] 
 
let simpleExpression() = 
    query { 
        for d in data do 
        select d 
        contains 5 
    } 
> simpleExpression();; 
val it : bool = true 

Query expressions have a list of query operators with which we can use the LINQ-like operations on the data:

    let designations = [| "CEO"; "CTO"; "Manager"; "Employee" |] 
 
    type Employee = 
        { 
            FirstName: string 
            LastName: string 
            Designation: string 
            Salary: int 
        } with 
            static member DummyData() = 
               let r = new System.Random() 
               seq { 
                    for i = 0 to 10 do 
                        let e = { 
               ...