iOS字符串的大小写互相转换

 NSString *str =@"we are togeter";

    NSString *Str = [struppercaseStringWithLocale:[NSLocalecurrentLocale]];

    NSLog(@"upperStr: %@", str);//转成全部大写

    NSString *Str1 = [StrcapitalizedStringWithLocale:[NSLocalecurrentLocale]];

   NSLog(@"capStr: %@", Str1);//转成首字母大写

    NSString *Str2 = [Str1lowercaseStringWithLocale:[NSLocalecurrentLocale]];

    NSLog(@"lowerStr: %@", Str2);//转成全部小写