indexOfObject in an NSMutableArray returning garbage value

Question

Trying to get index on an object in NSMutableArray. It is returning some garbage value, not getting why it is not returning index of particular item. Below is code i tried.

NSString *type = [dictRow valueForKey:@"type"];

if([arrSeatSel indexOfObject:type])
{
    NSUInteger ind = [arrSeatSel indexOfObject:type];
    [arrTotRows addObject:[arrSeatSel objectAtIndex:ind]];
}

type contains value "Gold". And arrSeatSel contains

 (
"Gold:0",
"Silver:0",
"Bronze:1"

How to check that. Please guide.

@iPhoneProgrammatically See Jeffery Thomas' answer and this: developer.apple.com/library/mac/documentation/Cocoa/Reference/… — Mick MacCallum
– Mick MacCallum, Commented Jun 5, 2013 at 11:41

Jeffery Thomas · Accepted Answer · 2013-06-05 20:23:48Z

7

The value you are getting is NSNotFound. You are getting NSNotFound because @"Gold" is not equal to @"Gold:0".

You should try the following

NSUInteger index = [arrSeatSel indexOfObjectPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop){
    return [obj hasPrefix:type];
}];

if (index != NSNotFound) {
    [arrTotRows addObject:[arrSeatSel objectAtIndex:index]];
}

UPDATE

-indexOfObjectPassingTest: is a running the following loop. NOTE: /* TEST */ is some code that returns true when the correct index is found.

NSUInteger index = NSNotFound;
for (NSUInteger i = 0; i < [array count]; ++i) {
   if (/* TEST */) {
       index = i;
       break;
   }
}

In my first sample, /* TEST */ is [obj hasPrefix:type]. The final for loop would look like.

NSUInteger index = NSNotFound;
for (NSUInteger i = 0; i < [arrSeatSel count]; ++i) {
   if ([arrSeatSel[i] hasPrefix:type]) {
       index = i;
       break;
   }
}

if (index != NSNotFound) {
    [arrTotRows addObject:[arrSeatSel objectAtIndex:index]];
}

I like -indexOfObjectPassingTest: better.

The [obj hasPrefix:type] part is just a different way to comparing strings. Read the -hasPrefix: doc for more details.

Hope that answers all your questions.

edited Jun 5, 2013 at 20:23

answered Jun 5, 2013 at 11:31

Jeffery Thomas

42.6k8 gold badges98 silver badges119 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

iPhone Programmatically Over a year ago

that i know but i need to apply this thing only, is it possible.

iPhone Programmatically Over a year ago

Tried even this way same result. NSUInteger ind = [arrSeatSel indexOfObject:@"Gold:0"];

Anupdas · Accepted Answer · 2013-06-05 12:00:26Z

2

Sometimes storing data properly can solve lot of hazzle. If I guess correctly

"Gold:0" denotes a circle of type Gold an its count 0.

You can try to reformat that to an array of items.

Such as

[
    {
        "Type": "Gold",
        "Count": 0
    },
    {
        "Type": "Silver",
        "Count": 0
    },
    {
        "Type": "Bronze",
        "Count": 1
    }
]

And then using predicate to find the index

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"Type == %@",@"Gold"];
NSUInteger index = [types indexOfObjectPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
    [predicate evaluateWithObject:obj];
}];

answered Jun 5, 2013 at 12:00

Anupdas

10.2k2 gold badges37 silver badges60 bronze badges

2 Comments

iPhone Programmatically Over a year ago

no you judged it wrong my friend it is the selection made of particular type.

Anupdas Over a year ago

@iPhoneProgrammatically I was just suggesting a way. Even if its selection it still holds rite. count denotes how many of those selection is in each circle.

Harish · Accepted Answer · 2013-06-05 11:30:49Z

1

You can try doing this.

[arrSeatSel enumerateObjectsUsingBlock:^(id object, NSUInteger idx, BOOL *stop) {

    // object - will be your "type"
    // idx - will be the index of your type.
}];

hope this helps.

answered Jun 5, 2013 at 11:30

Harish

1,51916 silver badges43 bronze badges

Comments

Shane Hsu · Accepted Answer · 2013-06-05 11:36:44Z

If I'm reading that correctly, you're saying that arrSeatSel contains three NSStrings, @"Gold:0", @"Silver:0", and @"Bronze:1", correct?

And then your NSString* type is basically @"Gold"

The first thing is Gold and Gold:0 are different strings, and that's just for starter.

As you are searching for a string in the array, you should take each string out, and do a string matching, not just a comparison. What I'm saying is this:

NSString* str1 = @"This is a string";
NSString* str2 = @"This is a string";
if ( str1 == str 2 ) NSLog(@"Miracle does happen!")

The conditional would never be true even though both NSStrings contain the same value, they are different object, thus are different pointers pointing to different blocks of memory.

What you should do here is a string matching, I will recommend NSString's hasPrefix: method here, as it seems to fit your need.

Collectives™ on Stack Overflow

indexOfObject in an NSMutableArray returning garbage value

4 Answers 4

2 Comments

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related