NSMutableAttributedString 显示角标 平方、几次幂

话不多说，直接贴代码

- (NSMutableAttributedString *)plainStringToAttributedUnits:(NSString *)string comment:(NSString *)commentStr haveSuperscrip:(NSString *) upDown;

{

    NSMutableAttributedString *attString = [[NSMutableAttributedString alloc] initWithString:string];

    UIFont *font = [UIFont systemFontOfSize:48.0f];

    UIFont *smallFont = [UIFont systemFontOfSize:18.0f];

    [attString beginEditing];

    [attString addAttribute:NSFontAttributeName value:(font) range:NSMakeRange(commentStr.length, string.length - commentStr.length)];

    [attString addAttribute:NSFontAttributeName value:(smallFont) range:NSMakeRange( 0, commentStr.length)];

    if (upDown.length>0) {//@"1" 上角标 @"-1" 下角标

        [attString addAttribute:(NSString*)kCTSuperscriptAttributeName value:upDown range:NSMakeRange(string.length - 1, 1)];

    }

    [attString endEditing];

    return attString;

}