1 00:00:05,710 --> 00:00:12,780 HEY WHAT'S UP GUYS I'M Jacob Bledsoe with Dev slopes that I'm in the last lesson we got our location 2 00:00:12,840 --> 00:00:18,180 updating for the device to keep track of distance which is really cool but we ran into one problem at 3 00:00:18,180 --> 00:00:18,680 the end. 4 00:00:18,680 --> 00:00:20,610 It was displaying everything in meters. 5 00:00:20,630 --> 00:00:27,000 And while that's not what we want we want to display everything in feet and we also want to round to 6 00:00:27,000 --> 00:00:30,970 the nearest hundredth place for decimals. 7 00:00:31,020 --> 00:00:32,410 So that's what we're going to do. 8 00:00:32,410 --> 00:00:38,670 I'm going to teach you how to do some cool type extensions for the double. 9 00:00:38,670 --> 00:00:44,430 And then we'll also be doing some other things like and date extensions later on and we're going to 10 00:00:44,430 --> 00:00:48,300 do a lot of cool extensions for just re-usability for formatting. 11 00:00:48,600 --> 00:00:50,950 And it's going to be really cool. 12 00:00:50,970 --> 00:00:56,730 So as you remember last time well before we get started let's go ahead and open up our terminal and 13 00:00:56,730 --> 00:01:01,640 I'm going to create a new branch get check out that should be Lesson 8. 14 00:01:01,980 --> 00:01:08,640 So if you need anything from this lesson you can go straight to this branch from the source code. 15 00:01:08,640 --> 00:01:09,030 All right. 16 00:01:09,030 --> 00:01:13,300 Now you can get going so if you remember let me just run the app again. 17 00:01:16,870 --> 00:01:22,540 And if you hit start run you're going to see our distance update and and if it's not moving remember 18 00:01:22,540 --> 00:01:25,570 de-bug location and just put it on city run. 19 00:01:25,810 --> 00:01:32,420 And as you can see crazy amount of decimal places and it's also displaying meters we don't want that. 20 00:01:32,440 --> 00:01:40,840 So let's end this simulator and let's right click our extensions folder and say new file and we just 21 00:01:40,840 --> 00:01:43,780 wanted a swift file. 22 00:01:44,030 --> 00:01:54,410 And I'm just going to call mine extensions and I'm going to be putting everything in this folder. 23 00:01:54,830 --> 00:01:57,160 And create. 24 00:01:57,320 --> 00:02:09,020 Right now as easy as extending a class you can just go extension and we're going to extend double and 25 00:02:09,020 --> 00:02:11,550 then opening and closing brackets. 26 00:02:11,570 --> 00:02:19,630 So one thing we need to do we need to convert meters to Miles Right. 27 00:02:19,970 --> 00:02:23,390 So let's go ahead and call our first function 28 00:02:25,640 --> 00:02:29,450 meters to Miles. 29 00:02:29,810 --> 00:02:33,200 And let's see we also 30 00:02:37,230 --> 00:02:41,390 we're going to want to round this to 31 00:02:44,300 --> 00:02:49,230 what you call it to the 100th or the 100th place. 32 00:02:49,250 --> 00:02:56,990 So let's go ahead and maybe make this a little more use of all we can actually pass in places as an 33 00:02:56,990 --> 00:02:58,080 integer. 34 00:02:59,620 --> 00:03:04,740 And what places will be is how many decimal places we want to display. 35 00:03:04,810 --> 00:03:05,430 OK. 36 00:03:05,590 --> 00:03:08,130 And then we're going to return a double value. 37 00:03:08,170 --> 00:03:08,710 OK. 38 00:03:08,770 --> 00:03:14,260 So to round to the nearest a certain decimal place you need a divisor. 39 00:03:14,260 --> 00:03:19,150 So let's go ahead and create that divisor. 40 00:03:19,150 --> 00:03:31,540 And the way this works is you need to use the the power function that's a built in math tool and how 41 00:03:31,540 --> 00:03:39,850 this works is let's see if we are going to take I'm just going to type this out and then explain it 42 00:03:39,850 --> 00:03:40,870 to you. 43 00:03:41,380 --> 00:03:44,370 OK so how this works is let's pretend we pass and. 44 00:03:44,390 --> 00:03:44,730 Right. 45 00:03:44,740 --> 00:03:50,090 We want it to the 100th place so point 0 0 we want that's what we want. 46 00:03:50,350 --> 00:04:00,090 So we're going to take 10 to the power of two which is a hundred and then we take that 100 square root 47 00:04:00,090 --> 00:04:01,650 it which is 10 again. 48 00:04:01,700 --> 00:04:08,350 And the reason I just picked that is because it's a super easy example for what this is doing. 49 00:04:08,360 --> 00:04:14,000 And obviously whatever you change this places to you you get slightly different numbers. 50 00:04:14,180 --> 00:04:22,400 And then if you multiply the number that we want by the divisor and then divide by the divisor it will 51 00:04:22,400 --> 00:04:26,840 take you to the right decimal place that you need. 52 00:04:26,840 --> 00:04:35,700 So with this override we're going to return return. 53 00:04:35,930 --> 00:04:37,940 We need a couple of parentheses here. 54 00:04:38,000 --> 00:04:45,700 And we're going to say self and that is the number that we're going to be changing from meters to Miles 55 00:04:45,760 --> 00:04:52,960 and I'll show you how to use that in a moment and we need to divide this by 1600 in nine point three 56 00:04:52,960 --> 00:04:54,330 four. 57 00:04:54,790 --> 00:05:02,730 And that is how many meters are in a mile. 58 00:05:02,740 --> 00:05:05,560 So there is one thousand six hundred nine meters. 59 00:05:05,650 --> 00:05:08,700 So in in one mile. 60 00:05:08,830 --> 00:05:15,580 So we're dividing whatever meters we're receiving by how many are in a mile and that's going to return 61 00:05:15,580 --> 00:05:19,670 a mile and then we need to multiply this by our divisor. 62 00:05:20,830 --> 00:05:22,920 And and our parentheses. 63 00:05:23,070 --> 00:05:31,590 And then we also want to round this rounded and with that being rounded we just divide by our divisor 64 00:05:32,100 --> 00:05:39,480 and that's going to return a nicely rounded function or number for us. 65 00:05:39,510 --> 00:05:41,990 So let's go back to our current run location. 66 00:05:42,450 --> 00:05:45,790 And if you remember our run distance is a double. 67 00:05:45,840 --> 00:05:49,760 So now that self that we were dividing by that's run distance. 68 00:05:49,920 --> 00:05:55,740 And since we overwrote it all the way to do is or added the extension is do with the dot and then we 69 00:05:55,740 --> 00:05:57,960 do look for meters to Miles. 70 00:05:57,960 --> 00:05:59,010 Pretty sweet. 71 00:05:59,220 --> 00:06:05,580 And if we pass in a two that's going to return to the nearest two decimal places. 72 00:06:05,580 --> 00:06:10,620 So let's go ahead and run this. 73 00:06:10,870 --> 00:06:15,710 And let's start our run and look at that. 74 00:06:15,750 --> 00:06:23,520 It's not spitting out crazy amount of numbers and it is giving us what we think is is Miles obviously 75 00:06:23,520 --> 00:06:25,710 we'll have to test it later. 76 00:06:25,920 --> 00:06:29,540 But I did take us out for a run and all my math did work. 77 00:06:29,580 --> 00:06:31,230 It matched my Apple Watch. 78 00:06:31,300 --> 00:06:32,660 That was pretty cool. 79 00:06:32,670 --> 00:06:36,940 So we just added an extension to type double which is really cool. 80 00:06:37,080 --> 00:06:40,730 And you can see just the power behind it. 81 00:06:41,130 --> 00:06:48,000 So let's change this place to let's say we want four places just to show that our function works. 82 00:06:48,000 --> 00:06:55,080 But we made this and it's super reuseable now and just adding an extension to type double now allows 83 00:06:55,080 --> 00:06:59,370 us to convert meters to Miles with any double number. 84 00:06:59,400 --> 00:07:00,450 Is really cool. 85 00:07:01,590 --> 00:07:02,400 And there we go. 86 00:07:02,400 --> 00:07:05,780 So now it's showing four decimal places which is really cool. 87 00:07:08,580 --> 00:07:09,520 All right guys. 88 00:07:09,540 --> 00:07:11,180 So I'm going to leave that one there. 89 00:07:11,190 --> 00:07:16,320 Let's go ahead and put this back to to before we end this let's pull up our terminal. 90 00:07:16,350 --> 00:07:33,410 Do a get ad period get commit dash em and we'll say we extended time double to convert meters to Miles. 91 00:07:33,410 --> 00:07:34,180 Cool. 92 00:07:34,200 --> 00:07:35,710 All right great guys. 93 00:07:35,820 --> 00:07:40,750 Next the next place we're going to be going is we're going to be setting up a timer. 94 00:07:40,770 --> 00:07:47,250 So when the run starts we're going to be starting a timer and then. 95 00:07:47,370 --> 00:07:47,930 Yeah. 96 00:07:48,030 --> 00:07:56,670 And then after that we have to just figure out the pace and we are then ready to go for one run but 97 00:07:56,700 --> 00:08:02,070 we start to save all of our data to realms that we're we're almost get into the meat of this course 98 00:08:02,430 --> 00:08:04,500 and I will see you guys in the next one.