In Elixir, if I want to check multiple boolean conditions, rather than some ugly mess of if/else logic, I can elegantly do this:
guess = 46
number_of_guesses = 3
cond do
number_of_guesses > 5 ->
IO.puts "Too many guesses! You lose."
guess == 46 ->
IO.puts "You guessed 46!"
guess == 42 ->
IO.puts "You guessed 42!"
true ->
IO.puts "I give up."
end
The above program generates the following result −
You guessed 46!
(Example derived from Tutorialspoint, but further contrived to demonstrate not every expression must contain the same variable.)
Does C# have anything similar or would I need to use if/else?
If you are matching against a value in almost all of the cases, you can still use a switch expression, with case guards:
int guess = 46;
int numberOfGuesses = 3;
Console.WriteLine(
guess switch {
_ when numberOfGuesses > 5 => "Too many guesses! You lose.",
46 => "You guessed 46!",
42 => "You guessed 42!",
_ => "I give up."
}
);
Notice that in the first arm, I matched anything (the underscore _ pattern) but only "when numberOfGuesses > 5". Or in this case you can even do fancier pattern matching:
Console.WriteLine(
(guess, numberOfGuesses) switch
{
(_, > 5) => "Too many guesses! You lose.",
(46, _) => "You guessed 46!",
(42, _) => "You guessed 42!",
_ => "I give up."
}
);
But of course, this is not possible in every situation.
If all the arms are unrelated conditions, using this sort of _ when ... construct feels a bit abusive, so alternatively, you can use a chain of ternary operators:
var x =
condition1 ?
someValue1 :
condition2 ?
someValue2 :
condition3 ?
someValue3 :
valueWhenNoConditionsAreTrue;
Though I feel even this can be a bit astonishing on first sight.
If you want to execute statements in those branches, rather than expressions, then you should just use a plain-old if-else-if structure, or if pattern matching can be used, a switch statement (but note that the _ when ... trick can't be used in a switch statement).