if statement in objective-c

Question

Can someone please help to explain the syntax of the following code for me? It meant to "return ? if _suit is nil, and return a corresponding string in an array if _suit is not nil".

- (NSString *)suit
{
    return _suit ? _suit : @"?";
}

Is it equivalent to the following code?

if (!_suit) {
    return @"?";
} else {
    return ?
}

Also, by the way, `return _suit ? _suit : @"?";` can be further simplified to `return _suit ?: @"?";`. — Rob, Jan 03 '15 at 22:44

score 3 · Accepted Answer · answered Jan 03 '15 at 22:22

3

Yes, this is a shortening of an if block. It is a conditional operator.

The format is as follows (same in many other languages):

condition ? ifTrue: ifFalse;

So your code:

return _suit ? _suit : @"?";

Is the same as

if(_suit) {
    return _suit;
} else {
    return @"?";
}

You can read more about it here.

answered Jan 03 '15 at 22:22

Alex K

8,269
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2

I wouldn't link to Java resources. There are subtle differences between Java and Obj-C. – Sulthan Jan 03 '15 at 22:38
Fair enough. If you have a good link to an Obj-C resource, go ahead and edit it in. – Alex K Jan 03 '15 at 22:50

score 2 · Answer 2 · answered Jan 03 '15 at 22:24

2

No it is not the same. The '?:' operator describes following it is just an if else statement as one-liner:

(if clause) ? : .

so in your case that would mean:

if (!_suit) {
   return @"?";
} else {
   return _suit;
}

answered Jan 03 '15 at 22:24

hasan

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if statement in objective-c

2 Answers2