macOS Unique elements in NSMutableSet !!!

[saleh.hi.62]

Hello guys,

i have got a problem with this object (NSMutableSet)!
as what i have read over the objective-c's document, i read that this object contain unique elements ! so look at the code that i have written and tell me why does it add duplicate elements !!!

	NSMutableSet *mutableSet = [[NSMutableSet alloc]init];
	[mutableSet addObject:@"value1"];
	[mutableSet addObject:@"value1"];
	[mutableSet addObject:@"value1"];

and

NSMutableSet *mutableSet =

[NSMutableSet setWithObjects:@"One", @"one", @"one", nil];

i want to know why i can add duplicate elements since it must not be!
i need to add unique elements, kindly help me how i can do this.

thanks

 

[ChOas]

    NSMutableSet *mySet = [NSMutableSet setWithObjects:@"One", @"one", @"one", nil];
    NSLog(@"mySet: %@", mySet);

prints:

2011-07-26 07:56:30.852 mytest[24466:902] mySet: {(
    One,
    one
)}

So the set only contains unique elements. Works perfect!

The docs say:

The NSMutableSet class declares the programmatic interface to a mutable, unordered collection of distinct objects.

It never says anywhere you can't add the same object to it multiple times. It only says it keeps a set of distinct objects.

I think we have an XY problem again. What is it you want to accomplish ?

 

[saleh.hi.62]

    NSMutableSet *mySet = [NSMutableSet setWithObjects:@"One", @"one", @"one", nil];
    NSLog(@"mySet: %@", mySet);

prints:

2011-07-26 07:56:30.852 mytest[24466:902] mySet: {(
    One,
    one
)}

So the set only contains unique elements. Works perfect!

The docs say:

The NSMutableSet class declares the programmatic interface to a mutable, unordered collection of distinct objects.

It never says anywhere you can't add the same object to it multiple times. It only says it keeps a set of distinct objects.

I think we have an XY problem again. What is it you want to accomplish ?

ok let me say in a different way, what i want to do is that to have a set of elements which are not duplicate!

for example if i want to add "one" and it is added to the object already it return a error and say it is exist already there, this is what i want.

 

[gnasher729]

ok let me say in a different way, what i want to do is that to have a set of elements which are not duplicate!

for example if i want to add "one" and it is added to the object already it return a error and say it is exist already there, this is what i want.

Please read the documentation for NSSet and NSMutableSet. The first thing you say is what NSSet does, the second thing is trivial if you read the documentation.

 

[ChOas]

ok let me say in a different way, what i want to do is that to have a set of elements which are not duplicate!

for example if i want to add "one" and it is added to the object already it return a error and say it is exist already there, this is what i want.

Then you just use containsObject: on your set to check if the object is already there and bail if needed.

 

[saleh.hi.62]

Then you just use containsObject: on your set to check if the object is already there and bail if needed.

thank you so much dude,

I am new in Objective C! could you plz illuminate me with an example? i really dont know how to use it!

 

[ChOas]

thank you so much dude,

I am new in Objective C! could you plz illuminate me with an example? i really dont know how to use it!

    NSMutableSet *mySet = [[NSMutableSet alloc] init];

    for (NSString *entry in [NSArray arrayWithObjects: @"1",@"2",@"3",@"1",@"5",@"2",@"2",nil]) {

     if ([mySet containsObject:entry]) {
      NSLog(@"Not adding %@, already in set",entry);
     } else {
      NSLog(@"Adding %@ to set",entry);
      [mySet addObject: entry];
     };
    };

 

[ChOas]

thank you so much dude,

I am new in Objective C! could you plz illuminate me with an example? i really dont know how to use it!

btw... I only started using sets yesterday, I'm a C programmer by origin and during my work now I usually program Perl (nobody dare laugh, okay ?)

But try and work your way through the documentation, it really all makes sense.

Like I said, I started sets yesterday. In my situation I need to add counted sets together. I had no clue if that was possible, so I extended NSCountedSet to allow me to add a set to a set I already had: [myCountedSet addCountedSet: newSet]. It's easy, just think about it and use the documentation.

According to Perl TIMTOWTDI (There Is More Than One Way To Do It) I'm adapting. I might not have found the best way to do this (although I looked for a better way) but it works for me.

Use the documentation, my friend!

(just as a note: I am learning Obj-C in my spare time, for personal stuff, I am still fooling around)