The ternary operator in a one-line function

Question

In Julia, I might want to write a function that returns 0 if the input is less than 1, or returns 2 if the input is greater than or equal to 1. This is a pretty simple function, and the verbosity of a five-line if else construct is probably excessive. So I'm trying to turn it into a one-line function. The best I can come up with is as follows:

f(x::Number) = begin (x < 1) && return(0); return(2); end

or

f(x::Number) = begin x < 1 ? (y=0) : (y=2); return(y); end

Are there any simpler ways to define this function?

Answer 1

julia> f(x::Number) = x < 1 ? 0 : 2
f (generic function with 1 method)

julia> f(0)
0

julia> f(1)
2

julia> f(0.99)
0

Answer 2

Alternative solution:

f(x::Number) = if (x < 1) 0 else 2 end

The if-elseif-else syntax in Julia will return the value of the expression that gets executed, which imho makes the C-like ternary operator rather superfluous. As in, all of its functionality is encompassed by a more readable alternative.

Looking at your previous attempts, I think it is worth mentioning that unlike in say Python, you rarely need to explicitly use return(). Often you can just return whatever your if-elseif-else blocks return, much like you would in most lisp dialects. Explicit return is like goto or break, something that you use to break control flow in exceptional cases.