objective-c nsmutablearray setValue forKey issue

Question

My codes:

NSArray *array = //objects here
NSMutableArray *mutarray = [[NSMutableArray alloc] init];

    for (NSString *s in array)
    {
        NSRange ran = [s rangeOfString:@"abc"];
    if (ran.location != NSNotFound)
    {
        int inde = [array indexOfObject:s];
        [mutarray setValue:[NSNumber numberWithInt:inde] forKey:s];
    } 
    }
    NSLog (@"mutarray: %@", mutarray);

I have tried NSMutableDictionary, but the content is unordered, so I prefer NSMutableArray to store Values and Keys orderly. But the output of NSLog showed nothing, what in the hell? The output of NSMutableDictionary showed four discoveries.

EDIT:

I even tried this code in front of the NSLog, but nothing shows:

[mutarray setValue:@"aha" forKey:@"jaha"];

EDIT: Guys, thanks for the answer! Now I understand. But the problem is that I store numbers as values and strings as keys. I have an NSMutableDictionary which is unordered. I still havent figured out how I should order it. I have the codes which I use, but it is not properly written:

NSInteger intSort(id num1, id num2, void *context)
{
    int v1 = [num1 intValue];
    int v2 = [num2 intValue];
    if (v1 < v2)
        return NSOrderedAscending;
    else if (v1 > v2)
        return NSOrderedDescending;
    else
        return NSOrderedSame;
}

In other method:

NSArray *ordered = [[mutdic allValues] sortedArrayUsingFunction:intSort context:NULL];
NSLog (@" ordered: %@", ordered);

The output shows only:

2011-08-29 22:36:03.998 scanner2[32359:207]  ordered: (
    1,
    5,
    9,
    16
)

The output should show this in ordered numerically:

2011-08-29 22:36:03.992 scanner2[32359:207] mutdic:  5 jam (geologi) en
2011-08-29 22:36:03.993 scanner2[32359:207] mutdic:  9 jax. (geologi)jammen
2011-08-29 22:36:03.994 scanner2[32359:207] mutdic:  1 beta (geologi).
2011-08-29 22:36:03.995 scanner2[32359:207] mutdic: 16 .(geologi),be;ta;

Darren · Accepted Answer · 2011-08-29 21:03:47Z

6

NSMutableArray does not store key/value pairs, it only stores objects. To add an object to the array, use the -addObject: method.

Use an array to store an ordered list of objects. Use a dictionary when you need to look up an object given some key. If you want an ordered list of a dictionary's keys, use

NSArray* orderedKeys = 
    [[myDictionary allKeys] sortedArrayUsingSelector:@selector(compare:)];

Edit: A couple of more options.

Just store an array of indexes, then look up the value in your main array of strings.

for (NSUInteger i = 0; i < [array count]; ++i)
{
    NSString* s = [array objectAtIndex:i];
    NSRange ran = [s rangeOfString:@"abc"];
    if (ran.location != NSNotFound)
    {
        [mutarray addObject:[NSNumber numberWithInt:i]];
    } 
}

for (NSNumber* index in mutarray)
{
    NSLog(@"Found %@:%@", index, [array objectAtIndex:[index intValue]]);
}

Store a two-dimensional array of indexes and strings:

for (NSUInteger i = 0; i < [array count]; ++i)

{
    NSString* s = [array objectAtIndex:i];
    NSRange ran = [s rangeOfString:@"abc"];
    if (ran.location != NSNotFound)
    {
        [mutarray addObject:
            [NSArray arrayWithObjects:[NSNumber numberWithInt:i],
                                      s,
                                      nil]]; 
    } 
}

edited Aug 29, 2011 at 21:03

answered Aug 29, 2011 at 20:24

Darren

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1 Comment

wagashi Over a year ago

It is the second option I needed! I love you :D

Rob Napier · Accepted Answer · 2011-08-29 20:26:15Z

3

NSArray is an ordered collection of objects. It is not a key-value mapping of objects. Calling setValue:forKey: on an NSArray is the same as sending setValue:forKey: to each of its items.

answered Aug 29, 2011 at 20:26

Rob Napier

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Comments

renam.antunes · Accepted Answer · 2011-08-29 20:26:49Z

1

This setValue:ForKey: method is not from the NSMutableArray, it is NSKeyValueCodingProtocol

In your case, since you want ordered results from a dictionary, you could take a look at the following methods:

– keysSortedByValueUsingSelector: – keysSortedByValueUsingComparator: – keysSortedByValueWithOptions:usingComparator:

If you need values sorted, just use allKeys which returns an array. You can them sort the array using any of the following methods:

– sortedArrayHint – sortedArrayUsingFunction:context: – sortedArrayUsingFunction:context:hint: – sortedArrayUsingDescriptors: – sortedArrayUsingSelector: – sortedArrayUsingComparator: – sortedArrayWithOptions:usingComparator:

answered Aug 29, 2011 at 20:26

renam.antunes

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user846945 · Accepted Answer · 2011-08-29 23:09:11Z

1

It looks like you want to store an ordered list of pairs. So NSArray of NSArrays

for (NSString *s in array)
{
    NSRange ran = [s rangeOfString:@"abc"];
    if (ran.location != NSNotFound)
    {
        int inde = [array indexOfObject:s];
        NSArray* pair = [NSArray arrayWithObjects:[NSNumber numberWithInt:inde],s,nil];
        [mutarray addObject: pair];
    } 
}

answered Aug 29, 2011 at 23:09

user846945

1 Comment

wagashi Over a year ago

Thanks. That is what Darren's second option looks like, except you made a NSMutableArray of two NSArrays.

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