objective-c none nil array comes up as nil in if/else statement

Question

The following code is not working as expected. I am setting an array after creating a view but before displaying. I used NSLog to test that the array is set but the if/else sees the array as empty.

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    NSLog(@"Planlist is nil %d / has %d objects", (planListArr == nil), [planListArr count]);

    if (planListArr == nil || [planListArr count] == 0) { ... }
    else {
        NSLog(@"Planlist is empty");
    }
}

Logs

2011-09-25 13:54:39.764 myVI[2938:13303] Planlist is nil 0 / has 8 objects
2011-09-25 13:54:39.765 myVI[2938:13303] Planlist is empty

PlanList is defined as

NSArray *planListArr;

@property (nonatomic, retain) NSArray *planListArr;

Can you show the code where your defining the array? That last bit of code is known as "declaring" the array. — chown
– chown, Commented Sep 25, 2011 at 18:02

Dave DeLong · Accepted Answer · 2011-09-25 18:01:39Z

4

if (planListArr == nil || [planListArr count] == 0) { ... }
else {
    NSLog(@"Planlist is empty");
}

Expanded, this becomes:

if (planListArr == nil || [planListArr count] == 0) {
    ...
} else {
    NSLog(@"Planlist is empty");
}

So basically, it looks like you have your NSLog() statement in the wrong branch.

answered Sep 25, 2011 at 18:01

Dave DeLong

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10 Comments

chown Over a year ago

+This is correct. The array is NOT empty or nil, so the else gets evald as true, and nslog prints.

Praveen-K Over a year ago

How the NSLog will work for else part "Planlist is empty" if planListArr is nil and its count return 0

Dave DeLong Over a year ago

@Praveen-K if the array is nil or empty, then "Planlist is empty" won't be logged (in the current code).

sho Over a year ago

sorry, the NSLog should be "Planlist is not empty".

Praveen-K Over a year ago

I still can bet, that @DaveDeLong answer is still wrong until he do not change the NSLog value "Plainlist is empty" to "Plainlsit is NOT empty"

|

Praveen-K · Accepted Answer · 2011-09-25 18:09:55Z

2

(!plainListArray && [plainListArray count]>0) ? NSLog(@"PlainList array has %d items",[plainListArray count] : NSLog(@"Oops! Array is not been initialized or it has no items");

answered Sep 25, 2011 at 18:09

Praveen-K

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