problem with Checking if object is exist in Array or not?

Question

Here I am trying to add object in array and checking if object is exist in array or not. for that I am using following code..

NSInteger ind = [arrActionList indexOfObject:indexPath];
if (ind >= 0 ) {
    [arrActionList removeObjectAtIndex:ind];
}
else {
    [arrActionList addObject:indexPath];
}

Here I suppose that I am doing right.. first I am checking for the index. If it is >= 0 I am removing the object else add a new object.

My problem is if there is no index found for object it assigns a garbage value to my integer variable. I suppose it should be -1 but it isn't so my next line in which I am removing object throw error.

ind = 2147483647

Any help...

aroth · Accepted Answer · 2011-04-19 10:43:29Z

9

The Official Documentation might be helpful.

In a nutshell, indexOfObject: returns the constant NSNotFound if the specified object is not in the array. The NSNotFound constant has a value of 0x7FFFFFFF, which is equal to 2147483647 in decimal.

Your code should behave correctly if you do:

NSInteger ind = [arrActionList indexOfObject:indexPath];
if (ind != NSNotFound) {
    [arrActionList removeObjectAtIndex:ind];
}
else {
    [arrActionList addObject:indexPath];
}

answered Apr 19, 2011 at 10:43

aroth

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Comments

Roger · Accepted Answer · 2011-04-19 10:43:07Z

7

If you don't need the value of ind later on , you could just write;

if ( [arrActionList containsObject:indexPath] ) {
     [arrActionList removeObject:indexPath;
}
else {
    [arrActionList addObject:indexPath];
}

Alternatively instead of testing ind >=0, use

if (ind != NSNotFound) { ...

because that's what the value 2147483647 actually is - it's not a 'garbage' value at all, it's telling you something useful.

answered Apr 19, 2011 at 10:43

Roger

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