1 00:00:01,620 --> 00:00:04,890 In this exercise, we're going to write a program 2 00:00:04,890 --> 00:00:09,870 that recreates something that I saw in a blog. 3 00:00:09,870 --> 00:00:12,840 I recently read this book called " " 4 00:00:12,840 --> 00:00:14,670 and it shocked me a little bit 5 00:00:14,670 --> 00:00:19,620 that we only have 4,000 weeks in our lifetime. 6 00:00:19,620 --> 00:00:22,470 And 4,000 is a number that we can all count to. 7 00:00:22,470 --> 00:00:23,700 It's a large number, 8 00:00:23,700 --> 00:00:27,990 but it's still relatively easy to understand. 9 00:00:27,990 --> 00:00:29,670 And there's this great blog post 10 00:00:29,670 --> 00:00:32,729 by Tim Urban called "Your Life in Weeks," 11 00:00:32,729 --> 00:00:34,710 and if you look in the description pane, 12 00:00:34,710 --> 00:00:37,590 you'll see a link to this blog post. 13 00:00:37,590 --> 00:00:42,590 You can see as he visualizes your 90 year human life 14 00:00:42,900 --> 00:00:45,600 in months and in weeks. 15 00:00:45,600 --> 00:00:47,820 And when it's all there on paper, 16 00:00:47,820 --> 00:00:50,790 and you can see each individual little box, 17 00:00:50,790 --> 00:00:55,790 it kind of shocks you just how little time we have on Earth. 18 00:00:56,040 --> 00:00:58,980 And if you really drill down into it and think about, 19 00:00:58,980 --> 00:01:01,170 well, how many summers do you have 20 00:01:01,170 --> 00:01:04,440 and how many Christmases do you get to spend, 21 00:01:04,440 --> 00:01:07,320 then it all gets a little bit existential. 22 00:01:07,320 --> 00:01:09,810 So, that is the goal. 23 00:01:09,810 --> 00:01:11,970 Today we're going to get existential 24 00:01:11,970 --> 00:01:13,860 and we're going to use programming 25 00:01:13,860 --> 00:01:15,330 and our skills that we've learned 26 00:01:15,330 --> 00:01:17,430 in order to calculate the number of weeks 27 00:01:17,430 --> 00:01:20,160 that we have left in our lifetime. 28 00:01:20,160 --> 00:01:25,050 The goal is to take the input as your age. 29 00:01:25,050 --> 00:01:28,890 So for example, here I've got somebody aged 15, 30 00:01:28,890 --> 00:01:32,280 and we're presuming that they're going to live until 90, 31 00:01:32,280 --> 00:01:34,050 we're going to be optimistic. 32 00:01:34,050 --> 00:01:35,430 And then we're going to calculate 33 00:01:35,430 --> 00:01:38,910 how many weeks they have left in their lifetime. 34 00:01:38,910 --> 00:01:42,030 And we're going to output this as a string 35 00:01:42,030 --> 00:01:45,630 with the exact format that you see in the description box 36 00:01:45,630 --> 00:01:48,960 which is "You have X weeks left." 37 00:01:48,960 --> 00:01:52,860 where X is replaced with the actual number of weeks 38 00:01:52,860 --> 00:01:54,123 that you have calculated. 39 00:01:55,320 --> 00:01:58,590 Pause the video, think about how you might do this, 40 00:01:58,590 --> 00:02:00,543 and try to complete this challenge. 41 00:02:04,230 --> 00:02:06,180 All right, let's go through the solution. 42 00:02:06,180 --> 00:02:07,860 The first thing we need to calculate 43 00:02:07,860 --> 00:02:10,560 is how many years they have left. 44 00:02:10,560 --> 00:02:12,390 So we're going to take 90 45 00:02:12,390 --> 00:02:15,690 and we're going to subtract it by their age. 46 00:02:15,690 --> 00:02:18,780 But again, remember that the input comes in 47 00:02:18,780 --> 00:02:21,000 as a string data type. 48 00:02:21,000 --> 00:02:25,680 In order to convert it into a whole number, an integer, 49 00:02:25,680 --> 00:02:30,060 we need to wrap the int() function around the age, 50 00:02:30,060 --> 00:02:32,343 just like what you see on line 3. 51 00:02:34,020 --> 00:02:36,450 In order to get to the number of weeks 52 00:02:36,450 --> 00:02:40,500 that that year is representing, 53 00:02:40,500 --> 00:02:43,740 we can drill it down through months 54 00:02:43,740 --> 00:02:47,970 or we can directly go there through the number of weeks. 55 00:02:47,970 --> 00:02:51,210 There are 52 weeks in a year, 56 00:02:51,210 --> 00:02:54,330 so we can simply multiply what's stored 57 00:02:54,330 --> 00:02:57,480 in the number of years by 52. 58 00:02:57,480 --> 00:03:00,300 If somebody was aged 41, 59 00:03:00,300 --> 00:03:03,840 then 90 - 41 = 49, 60 00:03:03,840 --> 00:03:07,680 and then 49 multiplied by 52 61 00:03:07,680 --> 00:03:12,090 is 2,548 weeks. 62 00:03:12,090 --> 00:03:15,900 Finally, we can print out using an f-string, 63 00:03:15,900 --> 00:03:19,860 telling the user they have however many weeks left, 64 00:03:19,860 --> 00:03:23,070 and we're substituting the weeks variable 65 00:03:23,070 --> 00:03:26,253 into the f-string using the curly braces here. 66 00:03:27,510 --> 00:03:29,660 And there you have it, that's the solution.