Variables and Function in F#

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By  Dhananjay Kumar   On  13 Jan 2011 09:01:40
Tag : F# , General
Variable and functions both defined with let construct in F#.
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Variable and functions both defined with let construct in F#.
Defining a integer variable

let a = 2;
 printfn "%d"a; 

In above snippet we defined a integer variable in F# with let constructs. In F# teypes autemetically get inferred. In above declaration type is automatically get inferred to int.


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The other way we can use language construct is

let var = expr1 in expr2 

we can evaluate the expr1 in expr2. First expr1 will get assigned to var1 and then will get evaluated to expr2.

Defining a function

Below we are defining a function called sqr. It is taking one parameter and calculating the square of the input parameter. 

let sqr n = n*n;;
 let a= sqr 5;;
 printfn "%d"a;;


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Above we saw the input parameter to the function got inferred to int. If we want to override default inference of the type then we need to explicitly tell the language about the type of input parameter.

Defining a function with explicit type at input parameter

let sqr (n:float) = n*n;;
let a= sqr 5.5;;
printfn "%f"a;;


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Hopes help and thank you for reading.

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About Author
Dhananjay Kumar
Occupation-Software Engineer
Company-Infosys Technolgies,Pune
Member Type-Gold
Joined date-20 Jul 2009
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Dhananjay Kumar is Microsoft MVP on connected system. He blogs at . You can follow him and reach him at
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