NSAttributedString superscript styling

Swift version:

let fnt = UIFont(name:"Helvetica", size:20.0)
let attributedString = NSMutableAttributedString(string:"GGG®GGG", attributes:[NSFontAttributeName : fnt!])
attributedString.setAttributes([NSFontAttributeName : fnt!.fontWithSize(10), NSBaselineOffsetAttributeName: 10], range: NSRange(location: 3, length: 1))

Swift 5

    let fnt = UIFont(name:"Helvetica", size:20.0)
    let attributedString = NSMutableAttributedString(string:"2.099", attributes:[NSAttributedString.Key.font : fnt!])
    attributedString.setAttributes([NSAttributedString.Key.font : fnt!.withSize(10), NSAttributedString.Key.baselineOffset: 10], range: NSRange(location: 4, length: 1))

Swift 4.2

In my example I want to subscript one instance of infinity symbol so my label's title will look like this:

let font = UIFont(name: "Helvetica", size: 14.0)

let attributedString = NSMutableAttributedString(string: "Solids(ΔE∞)•G7®", attributes: [NSAttributedStringKey.font : font!])

attributedString.setAttributes([NSAttributedStringKey.baselineOffset: -5], range: NSRange(location: 9, length: 1))

solidsLbl.attributedText = attributedString

The following code seems to do the trick:

UIFont *fnt = [UIFont fontWithName:@"Helvetica" size:20.0];

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"GGG®GGG"
                                                                                     attributes:@{NSFontAttributeName: [fnt fontWithSize:20]}];
[attributedString setAttributes:@{NSFontAttributeName : [fnt fontWithSize:10]
                                  , NSBaselineOffsetAttributeName : @10} range:NSMakeRange(3, 1)];