CODEWITHSUNDEEP
iosnsarray
user2519391
user2519391

Reputation: 41

NSArray with multiple Objects

I have a array with 10 objects , sometimes out of 10 objects ,some objects tends to null and if any of the object is null ,Its comes as empty in my UIPickerView but I want If the value of any object is null then it should be skipped.. what I am trying to do is

if([ob1 isEqualToString:@""]){
NSArray *Ar =[NSArray arrayWithObjects:ob2,ob3,ob4,ob5,ob6,ob7,ob8,ob9,ob10,Nil];}
else if [ob2 isEqualToString:@""] {}

but this will be long chain if i skip any null value this way..what should be the better way.

Upvotes: 1

Views: 1602

Answers (5)

Masa
Masa

Reputation: 3251

I had the same problem regarding nil objects and wrote a category on NS(Mutable)Array for that. So instead of:

NSMutableArray *array = [[NSMutableArray alloc] init];
if (ob0) [array addObject:ob0];
if (ob1) [array addObject:ob1];
if (ob2) [array addObject:ob2];
if (ob3) [array addObject:ob3];

You can use arrayWithObjectsNil for skipping nil objects:

id obs[] = { ob0, ob1, ob2, ob3 }; // Assuming obj1 and obj3 are nil. 
  NSLog(@"%@", [NSArray arrayWithObjectsNil:obs size:sizeof(obs)]);
> ( 0, 2 )

Or use arrayWithObjectsNull for transforming nil objects to [NSNull null]:

  NSLog(@"%@", [NSArray arrayWithObjectsNull:obs size:sizeof(obs)]);
> ( 0, "<null>", 2, "<null>" )

With the category it is also possible to use mutability and write it this way:

NSMutableArray *array = [[NSMutableArray alloc] init];
[array addObjectNil:ob0];   // skip, if ob0 is nil
[array addObjectNull:ob1];  // add [NSNull null], if ob1 is nil
...

There are also other methods with the same logic.

You'll find the category named Nilus on GitHub.

Upvotes: 0

CodenameLambda1
CodenameLambda1

Reputation: 1299

You should use NSMutableArray, instead of NSArray. Like as below:

NSMutableArray *m_array = [NSMutableArray array];

//Now you can check your objects if nil or empty string @"" and add it to the array.

if(object1==nil || [object1 isEqualToString:@""])
{
   //the string is empty do not add anything to array
}
else
{
  //we have a proper object
  [m_array addObject:object1];
}

//here you'll get the array will only proper objects.
//use this array to fill your pickerView data.

Upvotes: 0

D-eptdeveloper
D-eptdeveloper

Reputation: 2430

try to use this condition

if ((ob2 == [NSNull null]) && ob2 == nil) {

}

Upvotes: 0

kumar123
kumar123

Reputation: 889

First take an NSMutableArray. And an NSArray which is initialize with all objects including null. Then check if the object is not null then add on to the mutable array.

NSMutableArray *array = [[NSMutableArray alloc]init];
  for (int i=0;i<10;i++) {
    if (![[objectArray objectAtIndex:i] isEqualToString:@""]) {
      [array addObject:[objectArray objectAtIndex:i]];
    }
  }

Where ObjectArray is NSArray contain all the objects.We can see it takes less amount of coding.

Upvotes: 0

rmaddy
rmaddy

Reputation: 318804

If any of the 10 objects can be nil (note - use nil for Objective-C object references) then you need to do it the hard way:

NSMutableArray *array = [[NSMutableArray alloc] init];
if (ob1) [array addObject:ob1];
if (ob2) [array addObject:ob2];
if (ob3) [array addObject:ob3];
// ...
if (ob10) [array addObject:ob10];

This checks if each object is nil or not. If you also want to make sure it is not nil and it has a non-zero length value, change each if condition to:

if (ob1.length) ...

Upvotes: 1

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