Which coding style you use for ternary operator? [closed]

Answer 1

The ternary operator is generally to be avoided, but this form can be quite readable:

  result = (foo == bar)  ? result1 :
           (foo == baz)  ? result2 :
           (foo == qux)  ? result3 :
           (foo == quux) ? result4 : 
                           fail_result;

This way, the condition and the result are kept together on the same line, and it's fairly easy to skim down and understand what's going on.

Answer 2

a style I sometimes use, which I'm bringing up since it hasn't been mentioned, is like this:

$result = ($x == y)
        ? "foo"
        : "bar";

..but usually only if putting it all on one line makes it too long. I find that having the = ? : all line up makes it look neater.

Answer 3

PHP nested ternary operators behave differently.

This syntax passes all the following tests. Based on http://deadlytechnology.com/web-development-tips/php-ternary-syntax/

$myvar = ($x == $y)
?(($x == $z)?'both':'foo')
:(($x == $z)?'bar':'none');

.

See: http://au.php.net/ternary

Example #3 "Non-obvious Ternary Behaviour" explains why the following does not work in PHP.

$x = 1;
$y = 2;
$z = 3;   
$myvar = ($x == $y) 
       ? "foo" 
       : ($x == $z) 
         ? "bar" 
         : "none";  
$myvar == 'none'; // Good

$x = 1;
$y = 2;
$z = 1;   
$myvar = ($x == $y) ? "foo" : ($x == $z) ? "bar" : "none";  
$myvar == 'bar'; // Good

$x = 1;
$y = 1;
$z = 3;   
$myvar = ($x == $y) ? "foo" : ($x == $z) ? "bar" : "none";  
$myvar == 'bar'; // Bad!

$x = 1;
$y = 1;
$z = 1;   
$myvar = ($x == $y) ? "foo" : ($x == $z) ? "bar" : "none";  
$myvar == 'bar'; // Bad!

Answer 4

I'll dissent with the common opinion. I'm sort of like Imran with my conditional operator style. If it fits cleanly on one line, I keep it on one line. If it doesn't fit cleanly on one line, I do break it, but I use only a single tab (4 spaces; I have VS set to insert spaces for tabs) for the indent. I don't immediately jump to if-else, because a lot of the time the conditional operator makes more sense contextually. (If it doesn't make sense contextually, however, I simply don't use it.)

Also, I don't nest conditional operators. At that point, I do find it too difficult to read, and it's time to go to the more verbose if-else style.

Answer 5

$foo = (isset($bar)) ? $bar : 'default';

Answer 6

I personally only use it for an assignment of a variable (in java) for example :

String var = (obj == null) ? "not set" : obj.toString();

and (other example) when using function that doesn't allow null parameter such as :

String val; [...]
int var = (val == null) ? 0 : Integer.parseInt(val);