Get comma separated string for a property from a array of custom object

Question

I have a Array of custom objects with object having following properties optionID,OptionText. I want to get comma separated string for the optionID property. What would be the best approach to do this in iOS SDK.

for example NSString CommaSeperted = @"1,3,5" etc.

Answer 1

Category to NSArray:

@implementation NSArray(CustomAdditions)

- (NSString *)commaSeparatedStringWithSelector:(SEL)aSelector
{
    NSMutableArray *objects = [NSMutableArray array];

    for (id obj in self)
    {
        if ([obj respondsToSelector:aSelector]) {
            IMP method = [obj methodForSelector:aSelector];
            id (*func)(id, SEL) = (void *)method;
            id customObj = func(obj, aSelector);
            if (customObj && [customObj isKindOfClass:[NSString class]]) {
                [objects addObject:customObj];
            }
        }
    }
    return [objects componentsJoinedByString:@","];
}


@end

Example:

@implementation NSDictionary(Test)

- (NSString*)optionID
{
    return [self objectForKey:@"optionID"];
}

- (NSString*)OptionText
{
    return [self objectForKey:@"OptionText"];
}

@end

NSArray *customObjects = @[@{@"optionID": @"id1", @"OptionText": @"text1" }, @{@"optionID" : @"id2", @"OptionText": @"text2"}];//List of Your custom objects

NSString *commaSeparatedOptionIDs = [customObjects commaSeparatedStringWithSelector:NSSelectorFromString(@"optionID")];

NSString *commaSeparatedOptionTexts = [customObjects commaSeparatedStringWithSelector:NSSelectorFromString(@"OptionText")];