How to know if an NSMutableArray contains an object?

Question

I have a NSMutableArray Paths which contains many Path objects.

I would know if a specific path is in Paths.

I tried with :

if([paths containsObject:aPath]) {
    return YES;
}

but it doesn't work.

So, I tried also with Predicates :

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF contains %@", path];
NSArray *filteredArray = [self.paths filteredArrayUsingPredicate:predicate];

But I have an error, console say me that Paths is not a collection.

EDIT :

My array of paths is :

2013-04-04 20:57:36.465 numbs[42781:617] paths (
    "PATH: (\n    2,\n    2,\n    2,\n    5,\n    5,\n    6,\n    5,\n    4\n)",
    "PATH: (\n    2,\n    2,\n    2,\n    5,\n    5,\n    6,\n    4,\n    5\n)",
    "PATH: (\n    2,\n    2,\n    2,\n    5,\n    5,\n    4,\n    5,\n    6\n)",
    "PATH: (\n    2,\n    2,\n    2,\n    5,\n    5,\n    4,\n    6,\n    5\n)"
)

A path is :

PATH: (
    2,
    2,
    2,
    5,
    5,
    5,
    6,
    5,
    4
)

EDIT 2 :

I add in Path.m

- (BOOL)isEqual:(id)other
{
    return ([other isKindOfClass:[Path class]] &&
            [[other arrayOfNode] isEqual:self.arrayOfNode] &&
            [other somme] == self.somme &&
            [[other result] isEqual:self.result] &&
            [[other resultString] isEqual:self.resultString] &&
            [[other wayArray] isEqual:self.wayArray]);
}

- (NSUInteger) hash;
{
    return somme ^ [resultString hash] ^ [wayArray hash] ^ [arrayOfNode hash] ^ [result hash];
}

and in my controller :

 if([paths containsObject:aPath]) {
        return YES;
    }

But this method doesn't work too.

Answer 1

EDITED (for the new info in the post on 04013)

I would try something like this, if I were you:

Path *_path = ...; // you object you'd like to find
NSArray *_pathsArray = ...; // the array with lots of Path objects;

if ([[_pathsArray filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) {
    return ([evaluatedObject isEqual:_path]); // ... or whatever how you'd like to compare them
}]] count] > 0) {
    // it contains your _path object
} else {
    // it doesn't contain you _path object
}

---

OR

Path *_path = ...; // you object you'd like to find
NSArray *_pathsArray = ...; // the array with lots of Path objects;

__block BOOL _isInsideTheArray = FALSE;
[_pathsArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    *stop = _isInsideTheArray = ([obj isEqual:_path]); // ... or whatever how you'd like to compare them
}];

if (_isInsideTheArray) {
    // it contains your _path object
} else {
    // it doesn't contain you _path object
}

Answer 2

1. Your first instinct is right, use containsObject:

   if([paths containsObject:aPath]) {
       return YES;
   }
   

2. But, that didn't work for you because you're using a custom subclass and haven't implemented (I'm assuming) isEqual:. I don't know the path properties, so you'll have compare any instance variables path contains.

   - (BOOL)isEqual:(id)other
   {
       return ([other isKindOfClass:[Path class]] &&
           // TODO: instance variable checks like... 
           // [[other ivar] isEqual:_ivar] && 
           // [[other ivar2] isEqual:_ivar2]                 
   }
   

3. Finally, according to the docs, if you implement isEqual: you must also implement hash

   - (NSUInteger)hash
   {
       return [_ivar hash] ^ [_ivar2 hash];
   }
   

For more information see Implementing Equality and Hashing