alexshafran

#Collections in Swift

Arrays and dictionaries are the most common data stores in many applications. Swift has brought us a new generation of these collections, so let's take a look at how they compare to the collections found in Objective-C.

##Greatest Differences

###Typing One of the most obvious differences between collections in Objective-C and Swift is that Swift collections are explicitly typed. Typed collections are useful for many reasons, primarily because the system requires you to be precise with the content type you are working with. Any type mismatches will throw errors, which will help you avoid common mistakes.

###Mutability

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#import <Foundation/Foundation.h>

@interface NSObject (PropertyNames)

+ (NSArray *)propertyNames;
+ (NSArray *)propertyNamesRecursive:(BOOL)recursive;

@end

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@implementation UITableView (PreserveOffset)

- (void)reloadDataPreservingOffset
{
    CGSize contentSize = self.contentSize;
    CGPoint contentOffset = self.contentOffset;
    
    [self reloadData];
    
    CGSize newContentSize = self.contentSize;

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@implementation NSAttributedString (HTML)

+ (NSAttributedString *)attributedStringFromHTML:(NSString *)html
{
    NSDictionary *options = @{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType};
    NSData *data = [html dataUsingEncoding:NSUTF8StringEncoding];
    return [[NSAttributedString alloc] initWithData:data
                                            options:options
                                 documentAttributes:nil
                                              error:nil];

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@implementation NSFetchedResultsController (Helpers)

- (NSInteger)numberOfObjects
{
    return [[self.sections valueForKeyPath:@"@sum.numberOfObjects"] integerValue];
}

- (id)firstObject
{
    id<NSFetchedResultsSectionInfo> obj = [self.sections firstObject];

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    CGFloat multiple = 0.75;
    CFIndex theNumberOfSettings = 1;
    CTParagraphStyleSetting theSettings[1] = {{ kCTParagraphStyleSpecifierLineHeightMultiple, sizeof(CGFloat), &multiple }};
    CTParagraphStyleRef theParagraphRef = CTParagraphStyleCreate(theSettings, theNumberOfSettings);
    
    [string addAttribute:(id)kCTParagraphStyleAttributeName value:(__bridge id)theParagraphRef range:NSMakeRange(0, [string length])];

alexshafran

real text