Relational operators in F#

The relational operators in F# don’t behave in exactly the same way as they do in popular OOP languages like C# or Java.

The greater-than and less-than operators are the same, here’s an example:

let value = 5
let trueOrFalseGt = value > 5
let trueOrFalseLt = value < 5

The boolean values will be false as expected:

val trueOrFalseGt : bool = false
val trueOrFalseLt : bool = false

F# uses ‘=’ for equality as opposed to ‘==’ like in C# and Java:

let trueOrFalseEq = value = 5

val trueOrFalseEq : bool = true

So the equal sign in F# is used for both variable assignment and equality checking like in Visual Basic.NET .

Checking for inequality is a funny one:

<>

…so it’s nothing vaguely like ‘!=’ in C#:

let trueOrFalseNEq = value <> 5

val trueOrFalseNEq : bool = false

View all F# related articles here.