WEBVTT 00:00.480 --> 00:01.080 All right. 00:01.080 --> 00:06.360 So now that you've learned all about dictionaries, we're going to put all of that knowledge to test 00:06.360 --> 00:10.560 and to use by building a blind auction program. 00:11.360 --> 00:12.640 So here's the program. 00:12.880 --> 00:19.440 When you first run it, it's just going to show you the logo art and maybe a line that tells you what 00:19.440 --> 00:20.400 program you're in. 00:20.560 --> 00:22.320 And then it's going to ask you for your name. 00:22.320 --> 00:24.880 So let's say we have three bidders, right. 00:24.960 --> 00:31.240 So first go I go to the computer, I type in my name, I type in my bid and I hit enter. 00:31.680 --> 00:33.680 It asks me if there are any other bidders. 00:33.680 --> 00:34.600 I look around the room. 00:34.600 --> 00:37.040 I see two other colleagues, so I type. 00:37.080 --> 00:37.600 Yes. 00:38.040 --> 00:43.480 And now it clears the entire screen so that other people can't see what my bid was. 00:43.840 --> 00:47.960 So now I leave the computer and my colleague comes over. 00:48.200 --> 00:52.240 They type in their name and also their bid. 00:53.360 --> 00:57.680 And again they look around the room and they see there's one other person who wants to bid. 00:57.680 --> 00:58.960 So they hit yes. 00:59.090 --> 00:59.490 again. 00:59.490 --> 01:00.650 It clears their bid. 01:00.850 --> 01:04.130 And finally, the last person makes their bid. 01:04.730 --> 01:06.490 At this point, everybody has bid. 01:06.490 --> 01:08.130 So she's going to type no. 01:08.570 --> 01:15.930 And it's at this moment when our program is going to work out who has made the highest bid and print 01:15.930 --> 01:18.730 out who the winner is and what their bid was. 01:19.170 --> 01:24.290 This way, instead of competing with each other on bids, we actually all just give the highest price 01:24.290 --> 01:25.330 we're willing to pay. 01:25.570 --> 01:29.290 And this is known as quite an efficient way of making a bid. 01:29.450 --> 01:34.850 And you see that a lot in, say, the construction industry and government, etc.. 01:35.370 --> 01:42.010 Now, one of the most complex parts of actually trying to build this program is how do you clear the 01:42.010 --> 01:43.930 screen in between bids? 01:44.210 --> 01:53.890 Now, what I want you to do in your version of the code is I simply want you to print out a new line 01:53.890 --> 01:54.530 character. 01:54.530 --> 02:00.630 So if we print a string and the string happens to be just the backslash n. 02:00.630 --> 02:01.950 So just a new line. 02:02.150 --> 02:09.470 And then we can do this thing where we multiply this string by say 20 times or 100 times. 02:09.790 --> 02:14.750 And what this means is it's basically going to add 100 new lines. 02:14.830 --> 02:24.030 So if I go ahead and print hello and then I go ahead and have an input, um, type something. 02:24.430 --> 02:29.190 Now if I run this code, you'll see that hello was printed. 02:29.390 --> 02:33.950 And then immediately the next thing I did was to basically clear the screen. 02:33.950 --> 02:37.870 And I did that by typing backslash n 100 times. 02:38.030 --> 02:41.550 And this programmatically will scroll to this part. 02:41.550 --> 02:43.870 And now I can use this input. 02:43.870 --> 02:49.030 And the user won't be able to see the previous part unless they know how to scroll up. 02:49.230 --> 02:55.680 In addition, we've also got the starting art of the gavel logo, which you're going to put into the 02:55.680 --> 02:56.320 program. 02:56.600 --> 03:04.240 And the most important thing of all is that I want you to create a dictionary so that each person's 03:04.280 --> 03:09.960 name will be the key and their bid will be the value. 03:10.480 --> 03:15.600 And this dictionary is going to contain many of these key value pairs. 03:16.000 --> 03:21.960 And at the very end of the program, when everybody's done with bidding, then we're going to loop through 03:21.960 --> 03:25.680 that dictionary and figure out who has made the highest bid. 03:26.320 --> 03:33.560 If you want, this is a good time to analyze this completed project and see if you can create your own 03:33.560 --> 03:37.640 flow chart using something like Draw.io that I've shown you before. 03:37.880 --> 03:41.920 Or just take a piece of paper and a pen and draw out your flow chart. 03:42.400 --> 03:48.480 Now if you want a hint, then you can head over to the course resources and you'll get taken to the 03:48.480 --> 03:51.200 flow chart that I've created for this program. 03:51.480 --> 03:54.780 So spoiler alert I'm about to show you that flowchart. 03:54.980 --> 03:59.340 So if you don't want to see it and you want to create your own because it's a relatively simple program, 03:59.340 --> 04:02.620 then pause the video now and complete the challenge by yourself. 04:03.180 --> 04:09.140 Now, for everybody else who's still here, I want to show you this is a flowchart I've created to represent 04:09.140 --> 04:10.060 this program. 04:10.700 --> 04:12.300 So we start at the beginning. 04:12.300 --> 04:17.700 We first show the logo from that file, art dot Pi, and then we asked for a name input. 04:17.740 --> 04:19.020 We asked for their price. 04:19.420 --> 04:24.500 Now we're going to add the name and the bid into a dictionary, with the name as the key and the bid 04:24.500 --> 04:25.460 as the value. 04:25.900 --> 04:31.140 Now, once we're done with that, then we get to ask the user for another input and see if there are 04:31.140 --> 04:33.020 any other users who want to bid. 04:33.020 --> 04:37.900 So if they answer yes, then we're going to clear the screen and we're going to go back to here. 04:37.940 --> 04:41.180 Ask for another name, another price and so on and so forth. 04:41.500 --> 04:46.420 But if they say no, everybody's done with bidding, then we're going to call some sort of function 04:46.420 --> 04:52.550 that we have, which is going to loop through our dictionary that was created here and find the person 04:52.550 --> 04:58.310 who had the highest bid value and then declare them as the winner and print out their bid. 04:58.750 --> 05:03.030 So it's a relatively simple program, at least compared to other things that you've built so far. 05:03.350 --> 05:06.870 So this is the time to pause the video and give it a go. 05:25.110 --> 05:25.510 All right. 05:25.550 --> 05:32.150 Now I'm going to walk you through the solution, or at least my solution for the blind auction project. 05:32.630 --> 05:38.950 So the first thing that I'd like to do when we have something that is a large project is to break it 05:38.950 --> 05:39.310 down. 05:39.310 --> 05:42.510 So you saw me draw a flowchart. 05:42.790 --> 05:48.990 And the next step is I could translate that flowchart into several to do's in my code. 05:49.470 --> 05:56.360 So the first thing I'll probably want to do is to ask the user for some inputs. 05:56.840 --> 05:58.800 And the inputs that I need. 05:58.840 --> 06:07.360 If you take a look at the demo is it asks for what is your name and then what is your bid. 06:07.360 --> 06:09.920 And then it's got this dollar sign in front. 06:10.600 --> 06:14.600 And then it asks, are there any other bidders type yes or no. 06:14.920 --> 06:18.720 So we need a way of capturing these inputs right. 06:19.000 --> 06:21.760 So that could be R to do number one. 06:22.520 --> 06:31.040 Next we also need to save the data that the user gives us into a dictionary. 06:32.800 --> 06:41.280 And that way we can later loop through the dictionary where we have a list of name and then price. 06:42.080 --> 06:46.880 And we'll be able to figure out who is the name that had the highest price. 06:47.820 --> 06:56.260 Now, the next thing we might want to do is to figure out whether, if the user wants to continue adding 06:56.260 --> 06:57.140 new bids. 07:03.060 --> 07:09.860 And this might involve some sort of a loop so that we can keep going back to ask the user for input. 07:09.900 --> 07:13.180 But of course it will be a different user each time. 07:13.900 --> 07:22.140 Now the final thing to do is to actually go ahead and compare all the different bids and then figure 07:22.140 --> 07:26.300 out who has the highest bid in the dictionary. 07:28.860 --> 07:31.180 So that's pretty much all there is to it. 07:31.180 --> 07:34.980 And let's go ahead and tackle it one by one. 07:35.580 --> 07:39.500 So firstly let's ask the user for some input. 07:39.500 --> 07:43.700 So let's save their name into a variable called name. 07:44.060 --> 07:48.110 And then we'll use an input to ask them, what is your name? 07:49.150 --> 07:53.550 And then we'll add a colon, maybe a space so they can type their name here. 07:54.390 --> 07:59.110 And then once they've typed their name we'll ask them for a price. 07:59.430 --> 08:01.750 So again it's going to be an input. 08:01.750 --> 08:04.390 And we're going to say what is your bid. 08:05.070 --> 08:11.950 And now we're going to add a dollar sign or whatever currency you work with in front of their bid. 08:12.190 --> 08:14.990 But remember that they're going to write a number in here. 08:14.990 --> 08:17.670 And inputs are strings. 08:17.910 --> 08:20.350 You can see that it's going to give you a string. 08:20.350 --> 08:26.870 So in order for us to be able to save it into our dictionary as a number, I'm going to convert it to 08:26.910 --> 08:27.950 an integer. 08:27.990 --> 08:33.110 Now of course, if you want bids that have floating points decimal places, you could also convert this 08:33.150 --> 08:34.190 into a float. 08:34.670 --> 08:42.990 So now that we've got our number and our name, the next thing to do is to save that data into a dictionary. 08:43.930 --> 08:49.650 So if we have a dictionary that we call, let's say we call it bids. 08:50.170 --> 08:53.010 And we started out as an empty dictionary. 08:53.530 --> 09:00.370 Then once we've gotten hold of the data from the user, the name and the price, we can then add to 09:00.410 --> 09:02.290 this dictionary of bids. 09:02.490 --> 09:03.970 So we can say bids. 09:03.970 --> 09:06.610 And then the key is going to be their name. 09:06.930 --> 09:09.570 And we can set it equal the value. 09:09.930 --> 09:16.930 So if this is at all unfamiliar then you might need to go and review the lesson where we learnt about 09:16.930 --> 09:22.530 dictionaries, how to modify, how to edit, how to add, how to create empty dictionaries. 09:22.810 --> 09:29.130 But this is essentially the process to save the data into our dictionary in this format. 09:29.730 --> 09:36.690 So now we need to ask the user whether if there are any new bids that need to be added. 09:37.090 --> 09:44.500 So we could probably have a variable called should continue and we could set that to equal an input. 09:44.860 --> 09:46.380 And our prompt could be. 09:46.700 --> 09:49.820 Are there any other bidders. 09:50.620 --> 09:53.740 And we can say type uh yes. 09:55.620 --> 09:59.380 Um or no. 10:01.940 --> 10:06.020 And then we could add a new line so that they type on the next line. 10:06.300 --> 10:09.300 And now we have this variable should continue. 10:09.820 --> 10:18.900 So how can we use this variable to go back to the beginning and ask for the new person's name price. 10:18.900 --> 10:21.860 And save it to our bids variable. 10:22.220 --> 10:27.300 Well we would probably need some form of a loop right. 10:27.780 --> 10:32.060 So let's go ahead and use our friend the while loop. 10:32.540 --> 10:35.140 Now what is the variable that we'll check. 10:35.140 --> 10:43.520 Let's say that we had a variable called continue Bidding and we set it to equal true. 10:43.560 --> 10:47.840 To start off while continue bidding is true. 10:48.280 --> 10:56.800 Then we are going to keep asking the user for their name and price, and then we're also going to keep 10:56.800 --> 11:02.280 saving their bids into this variable called bids. 11:03.280 --> 11:12.640 And then finally we're also going to ask them what is their choice whether if there are any more people 11:12.640 --> 11:15.440 who are going to enter this auction. 11:15.880 --> 11:19.720 So we can now delete all these bits of repeated code. 11:20.200 --> 11:27.960 And if you think about this dictionary, we need it to be outside of the while loop so that it accumulates 11:27.960 --> 11:31.920 and it doesn't reset to zero every time the while loop runs. 11:32.360 --> 11:39.250 If we had this inside the while loop, then every single time we repeat the loop we're going to lose 11:39.250 --> 11:43.090 all of our previous data, so let's keep it outside. 11:44.450 --> 11:51.970 Now finally, we need to compare the bids in the dictionary once the user is done. 11:52.290 --> 11:57.210 So once the user is done, then we would get a no. 11:57.650 --> 12:02.050 And if the user was not done, we would get a yes. 12:02.490 --> 12:11.170 Now because this is going to be user input, yes or no, it's usually a good idea to add dot lower onto 12:11.170 --> 12:17.730 this so that when we're comparing it using our if statement, we know that it's always going to be lowercase. 12:18.330 --> 12:23.690 So if the should continue input is equal to no. 12:24.010 --> 12:28.770 Well in that case we need to compare the bids in our dictionary. 12:29.130 --> 12:36.370 Now, since this comparison in our dictionary is kind of like a separate piece of functionality, it's 12:36.500 --> 12:40.340 probably a good idea to create a separate function for it. 12:40.580 --> 12:48.220 That way we can reuse it, and we can also modularize our code so that it only does that function, 12:48.220 --> 12:53.100 and we can keep it outside of the main body of our script. 12:53.700 --> 12:59.500 So let's go ahead and create a function which I'll call find highest bidder. 13:00.420 --> 13:06.260 And this is going to take an input in the sense of a bidding dictionary. 13:07.140 --> 13:09.700 Now this is just a parameter. 13:09.700 --> 13:12.340 We can pass anything we want in here. 13:12.500 --> 13:17.180 But we know that what we're going to pass is actually this dictionary of bids. 13:17.780 --> 13:24.620 So what we want to do is we want to loop through our dictionary bidding dictionary. 13:25.140 --> 13:29.380 And we're going to look for each bit. 13:29.500 --> 13:33.580 So for bid in bidding dictionary would be nice. 13:33.580 --> 13:41.040 But as you might remember, when we loop through dictionaries, what happens is we actually loop through 13:41.080 --> 13:42.400 each of the keys. 13:42.880 --> 13:49.440 So if our dictionary is structured like this and we say for something in bidding dictionary, we're 13:49.440 --> 13:52.160 going to be getting hold of each of the names. 13:52.360 --> 13:57.040 So let's say for bidder in bidding dictionary. 13:57.040 --> 14:00.840 That way we're not confused as to what this value will be. 14:01.360 --> 14:10.280 Then we can set their bid amount to be equal to the bidding dictionary. 14:11.360 --> 14:16.080 And then using the square brackets to tap into that key the current bidder. 14:16.360 --> 14:22.760 And this is how we get hold of the value in a dictionary when we're looping through it. 14:22.760 --> 14:25.920 And this is something we covered in previous lessons as well. 14:26.800 --> 14:34.530 So now we need to figure out what is the largest number in terms of this bid amount when we loop through 14:34.730 --> 14:36.250 the bidding dictionary. 14:36.570 --> 14:38.690 Now, there are several ways of doing this. 14:38.730 --> 14:48.490 And the most, uh, easy to logic through way is to simply set something called a highest bid. 14:49.090 --> 14:51.290 And we can set it to equal zero. 14:51.650 --> 14:58.010 And then every time we loop through a new bidder and we get hold of that bid amount, we can check to 14:58.050 --> 15:04.490 see if the bid amount is greater than the current highest bid. 15:05.010 --> 15:12.610 And in that case, then the highest bid is going to be set to the bid amount. 15:13.570 --> 15:20.050 So now we can set a winner so we know who this person is, right? 15:20.250 --> 15:29.090 If at this point of the loop our highest bid is equal to the bid amount, then at the same time the 15:29.210 --> 15:33.270 winner is going to be the person who has that highest amount. 15:33.550 --> 15:38.950 So we can also reset the winner to the current bidder. 15:41.790 --> 15:44.390 Now outside of the for loop. 15:44.390 --> 15:51.870 So once all of the loop has completed going through each of the entries in our dictionary, we've gone 15:51.870 --> 15:53.750 through everybody's bids. 15:54.110 --> 15:57.070 Then we can go ahead and print the winner. 15:57.070 --> 16:00.950 So let's create an F string and say the winner is. 16:01.110 --> 16:04.670 And then we can insert this winner variable. 16:05.110 --> 16:08.390 And we can say with a bid of. 16:08.630 --> 16:14.430 And then our dollar sign and the highest bid can go in here as well. 16:15.030 --> 16:19.550 So that completes our finding highest bidder function. 16:19.950 --> 16:26.910 And the thing that I said earlier where I said there's many ways of doing this, you can also actually 16:26.910 --> 16:29.720 just simply use the max function. 16:29.720 --> 16:39.000 Now Python has a max function that can figure out what is the maximum value of all of the values in 16:39.000 --> 16:40.000 a dictionary. 16:40.440 --> 16:46.360 So I've got my Python console open here just to build a separate dictionary. 16:46.680 --> 16:51.000 So here I've got a dictionary representing the fruits that are in my house. 16:51.200 --> 16:54.400 And I want to know which fruit I have the most of. 16:54.840 --> 17:03.120 So what I can do is I can use the max function, pass in my dictionary fruit, and then after a comma, 17:03.120 --> 17:10.600 I could set the key to equal the fruits dot get. 17:11.120 --> 17:17.040 And what this line of code is going to do is it's going to look through the values of all of the items 17:17.040 --> 17:22.480 in my dictionary, compare them against each other, do a whole bunch of number crunching, and then 17:22.480 --> 17:27.200 give me the key that corresponds to the maximum value. 17:27.570 --> 17:32.930 Now, if you did a bit of googling and went on to StackOverflow because you thought to yourself, surely 17:32.930 --> 17:36.650 Python must be able to figure this out without me having to work it out? 17:36.650 --> 17:38.210 Then you are right. 17:38.530 --> 17:44.890 But I think given that most people are learning Python from scratch and they don't have any knowledge 17:44.890 --> 17:54.690 of other programming languages, this is super mysterious, and I recommend to actually always try to 17:54.730 --> 18:02.170 go from first principles and just simply work it out, because the code is not that complicated and 18:02.170 --> 18:07.490 down the line, this will be a lot easier to figure out than some code you got off the internet. 18:07.570 --> 18:09.810 And besides, we're learning at the moment, right? 18:09.970 --> 18:12.450 So it's always good to write more code. 18:13.050 --> 18:17.250 So we've got our dictionary comparison function. 18:17.250 --> 18:20.210 We just need to use it in our while loop. 18:20.690 --> 18:23.570 So if should continue is equal to no. 18:23.610 --> 18:25.950 That means everybody's done with their that bids. 18:26.190 --> 18:35.590 And this dictionary is now full, so we can now pass that dictionary over to the find highest bidder 18:35.590 --> 18:36.350 function. 18:36.750 --> 18:41.510 So we can firstly set continue bidding to false. 18:41.510 --> 18:43.270 So we exit our loop. 18:43.710 --> 18:52.150 And then we set our find highest bidder to work on our dictionary of bids. 18:52.590 --> 18:56.110 Now you'll notice that at the moment I have this red underline. 18:56.110 --> 19:00.390 And I'm not getting any autosuggest for my function down here. 19:00.670 --> 19:07.150 And that's because we need to declare this function or create this function before we use it. 19:07.150 --> 19:12.750 So if I move it all the way up there, then we now have a working bit of code. 19:13.390 --> 19:20.350 So finally the only other thing we need to do is to check if they typed in. 19:20.390 --> 19:20.830 Yes. 19:20.830 --> 19:27.720 So if should continue is equal to yes that means they want to go back to the beginning of the loop and 19:27.720 --> 19:29.760 enter the next person's name. 19:30.160 --> 19:36.920 But remember that what we want to do is to clear the screen when that happens. 19:37.120 --> 19:44.960 So if I type yes, I don't want the previous person to see the bid because it's a blind auction, right. 19:45.000 --> 19:51.040 So as I mentioned previously, in order to clear the screen, we're simply just going to print out the 19:51.040 --> 19:52.320 new line character. 19:52.320 --> 19:57.960 So backslash n and we can print it out 20 times or 100 times or however many times you want. 19:58.400 --> 20:02.800 And then it's going to loop back to the beginning of the while loop asking the next person. 20:03.240 --> 20:05.000 So let's try this out. 20:05.160 --> 20:13.120 Let's say that we have one person called Angela who wants to bid $12 for this half eaten apple. 20:13.760 --> 20:22.260 And then we have another bidder who is called John, who wants to bid only $3. 20:22.700 --> 20:28.700 And finally we have Kate, who only wants to pay $1. 20:29.140 --> 20:32.860 So now if we go ahead and say no, there are no more bidders. 20:32.860 --> 20:38.180 It tells us that the winner is Angela with a bid of $12. 20:38.460 --> 20:45.100 And now all we need to do is to put in the final finishing touch, which is to import and print our 20:45.100 --> 20:45.700 logo. 20:46.100 --> 20:52.380 So import art and then we'll go ahead and print art dot logo. 20:52.820 --> 20:56.620 And that will complete this project. 20:56.980 --> 21:02.020 So as always you can go into the solution dot pi to view my solution. 21:02.260 --> 21:05.460 You can improve the project to your desire. 21:05.660 --> 21:12.180 And you can also go back and review some of your code to make sure that everything works as expected. 21:13.180 --> 21:18.100 Now, tomorrow will be a new day and we'll be learning some more Python. 21:18.260 --> 21:20.540 So get some rest and I'll see you soon.