Ternary passing of arguments

Question

In Java is it possible to use ternary to pass multiple arguments into a method call?

For example - in a method have:

    print(degree == 270 ? "e", 5 : "t", 6);

which calls:

    public void print(String s, int t){

    }

By using the ternary I want to pass in e and 5 OR t and 6. Without the need of having to duplicate code - like:

    print(degree == 270 ? "e" : "t", degree == 270? 5 : 6);

I don't think some understand, I don't want to use this method above, it runs the check an unnecessary time.

I think `degree == 270 ? print("e", 5) : print ("t", 6);` is the easiest to read. — Tom, May 29 '13 at 11:22
@SubhrajyotiMajumder Not even then, when used as an *Expression Statement*, which is clearly the intention here. — Marko Topolnik, May 29 '13 at 11:24
I'm pretty sure it's not possible to do it how OP wants, that's why I was offering what I believe is the best solution — Tom, May 29 '13 at 11:29
Why is this necessary? You can fit an if statement on to a single line if you're so inclined. — Bob Flannigon, May 29 '13 at 11:39
I know the print(degree == 270 ? "e" : "t", degree == 270? 5 : 6); works, but it's not what I want. I know I can fit it in a single line, but that's not the question. I know what I can do with Java, I'm just curious. — Jim, May 29 '13 at 11:41
Why was this closed as "not a real question".. this is a joke. — Jim, May 31 '13 at 15:09

max_ · Accepted Answer · 2013-05-29T11:43:37.440

1

Why not

    (degree == 270) ? print("e", 5) : print("t", 6);

EDIT: apparently does not work in java :/

edited May 29 '13 at 11:43

answered May 29 '13 at 11:23

max_

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Seriously? I'm pretty sure it does at least in c++ – max_ May 29 '13 at 11:30
It's easy enough to check... for your and OP's version alike :) – Marko Topolnik May 29 '13 at 11:31
upps, thx Tom. @Marko: there's a subtle difference between mine and OP's if you look closely;). But ok, if java does not allow this.. what the heck. – max_ May 29 '13 at 11:37
I'm saying that it is as easy for OP to check his version as it is for you to check yours. Both of you will find the same answer, though. – Marko Topolnik May 29 '13 at 11:39
Yeah this would have worked fine, but as said, doesn't compile.. :( – Jim May 29 '13 at 11:47
@user1776888 What kind of compile error are you getting? It's working for me. – Tom May 29 '13 at 11:49
@Tom Post the complete example which is working for you. It can work only as an expression and not the way you have posted it. – Marko Topolnik May 29 '13 at 11:50
Oh I see what you mean, doesn't work when print is void – Tom May 29 '13 at 11:57

score 1 · Answer 2 · edited May 29 '13 at 13:46

1

It would be possible if your expression consists of a wrapper object that has both of the values (s and t) as variables, but then you would have to instantiate both. For making your code better, I would try something like:

if(degree == 270) {
    print("e", 5);
}
else {
    print("f", 6);
}

or

switch(degree) {
    case 270:
        print("e", 5);
        break;
    default:
        print("f", 6);
        break;
}

as long as you compare to absoute values (not ranges).

I know it's not what you're looking for, but normally, in enterprise environments, this is the notation that would be recommended as it's the easiest to understand for others that will mantain the code and reduces risk of errors if some novice programmer has to change something.

At the end, the compiled code will be efficient either way. In fact, I'm thinking that your second option will go through the conditional expression twice, in which case it would be better just to use one of the alternatives I wrote.

Regards

edited May 29 '13 at 13:46

Menno

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answered May 29 '13 at 11:30

Martin

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I work in industry and I was told ternarys are easier to maintain and look at. I know wrapping it would have worked but that's unnecessary. Thanks anyway. – Jim May 29 '13 at 11:44
1

Ternaries are great, I agree. `return test? "a" : "b"` puts less mental load on the reader than `if (test) return "a" else return "b"` because in the former case it is known up front that we are unconditionally returning, and it is only left to decide what, wheras with `if` we must carefully inspect both clauses to make sure. – Marko Topolnik May 29 '13 at 11:48
Well, it's always a matter of opinion from people in each enterprise. However, the longer code is really easy to look at. What makes it risky is if you don't use the braces on 1 line if statements, often a programmer adds a line and forgets that there are no braces... At the end, I think it's a matter of having coding standards... – Martin May 29 '13 at 11:50
@Marko I agree, specially in the case you state because you're avoiding multiple return statements in a method which is also often considered as a bad practice... As I said, it will often depend on the policies of the enterprise... – Martin May 29 '13 at 11:52

score 0 · Answer 3 · answered May 29 '13 at 11:19

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A conditional expression (that's the official name) is an expression just like any other Java expression. As far as the surrounding method call is concerned, only its result matters. So clearly, you cannot use one expression to specify two arguments because each argument is its own expression.

answered May 29 '13 at 11:19

Marko Topolnik

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That's not really an answer to the question. He asks whether it is possible to return MULTIPLE results depending on the condition. – Menno May 29 '13 at 11:21

Ternary passing of arguments

3 Answers3