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I have an array of strings that I want to use as the filter for another array of dictionaries that is created from a plist. For example, if I had a plist of dictionaries that looked like so:

Key:      Value:
car1      audi
car2      bmw
car3      bmw
car4      audi
car5      jaguar

and my array of strings was "audi, jaguar". How would I code it so that I can create a new array that would return "car1, car4, car5"? Hope this makes sense. Or better yet, how can I walk down this dictionary and filter it based on a value and then create a new array of dictionaries to use.

Code:

-(void)plotStationAnnotations {

desiredDepartments = [[NSMutableArray alloc] init];

BOOL tvfrSwitchStatus = [[NSUserDefaults standardUserDefaults] boolForKey:@"tvfrSwitchStatus"];
BOOL hfdSwitchStatus =  [[NSUserDefaults standardUserDefaults] boolForKey:@"hfdSwitchStatus"];

if (tvfrSwitchStatus) {
    NSString *tvfr = @"TVF&R";
    [desiredDepartments addObject:tvfr];
}
if (hfdSwitchStatus) {
    NSString *hfd = @"HFD";
    [desiredDepartments addObject:hfd];
}

NSLog(@"Array 1 = %@", desiredDepartments);

NSString *path = [[NSBundle mainBundle] pathForResource:@"stationAnnotations" ofType:@"plist"];
NSMutableArray *anns = [[NSMutableArray alloc] initWithContentsOfFile:path];

NSMutableArray *newDictionaryArray = [NSMutableArray array];
for (NSDictionary *dictionary in anns) {
    for (NSString *string in desiredDepartments) {
        if ([dictionary allKeysForObject:string]) {
            [newDictionaryArray addObject:dictionary];
            break;
        }
    }
}

NSLog(@"Array = %@", keyMutableArray);

for (int i = 0; i < [keyMutableArray count]; i++) {

    float realLatitude = [[[keyMutableArray objectAtIndex:i] objectForKey:@"latitude"] floatValue];
    float realLongitude = [[[keyMutableArray objectAtIndex:i] objectForKey:@"longitude"] floatValue];

    StationAnnotations *myAnnotation = [[StationAnnotations alloc] init];
    CLLocationCoordinate2D theCoordinate;
    theCoordinate.latitude = realLatitude;
    theCoordinate.longitude = realLongitude;
    myAnnotation.coordinate = theCoordinate;
    myAnnotation.title = [[keyMutableArray objectAtIndex:i] objectForKey:@"station"];
    myAnnotation.subtitle = [[keyMutableArray objectAtIndex:i] objectForKey:@"department"];
    [mapView addAnnotation:myAnnotation];
}
}
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2 Answers

up vote 0 down vote

May be something like 

NSArray *array1;
if([array1 containsObject : someValue])

can help. someValue can be your values you want to check if they exist in array1.

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up vote 0 down vote

You can do something like this to filter by keys:

NSArray *keysToLookFor = [NSArray arrayWithObjects:@"car1", @"car4", @"car5", nil];
NSArray *foundObjects = [dictionary objectsForKeys:keysToLookFor notFoundMarker:nil];

Or something like this to filter by values:

NSString *valueToLookFor = @"Audi";
NSArray *keyArray = [dictionary allKeysForObject:valueToLookFor];

// To filter by multiple values
NSArray *valuesToFilterBy = [NSArray arrayWithObjects:@"Bmw", @"Audi", nil];
NSMutableArray *keyMutableArray = [NSMutableArray array];
for (NSString *string in valuesToFilterBy) {
    [keyMutableArray addObjectsFromArray:[dictionary allKeysForObject:string]];
}

Updated answer for dictionaries in arrays:

NSArray *dictionaryArray; // The array of dictionaries that you have
NSMutableArray *newDictionaryArray = [NSMutableArray array];
NSArray *valuesToFilterBy = [NSArray arrayWithObjects:@"Bmw", @"Audi", nil];
for (NSDictionary *dictionary in dictionaryArray) {
    for (NSString *string in valuesToFilterBy) {
        if ([dictionary allKeysForObject:string]) {
            [newDictionaryArray addObject:dictionary];
            break;
        }
    }
}
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Where you have 'dictionary'? I have an array of dictionaries... so how would I do it that way? – Jon Erickson Dec 10 '12 at 6:29
Im not sure what you mean when you say that you have an array of dictionaries, your plist should be just one dictionary with the keys and values that you provided above in that one dictionary. Is each value/key that you provided above in separate dictionaries? If so, you should keep them in one dictionary, not in an array of dictionaries. – Kris Gellci Dec 10 '12 at 6:32
I have an array of about 30 dictionaries. Each dictionary has 4 elements in it. – Jon Erickson Dec 10 '12 at 6:33
Have update answer to account for dictionaries in an array, I wasn't sure if you wanted to keep a filtered array of the dictionaries or a filtered array of keys for the specified values you filter with but the code can be easily altered to keep a filtered array of dictionaries. – Kris Gellci Dec 10 '12 at 6:39
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