| 00:07 | greetings. This video is a short to modules in python. Let's get |
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| 00:18 | . So it is also module five the course and turns out we use |
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| 00:25 | same word. Again, it's also python modules. What is a |
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| 00:33 | A module in a in python is python cord that's written by somebody for |
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| 00:41 | by others. It's that's that's basically it's about. Something you develop and |
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| 00:48 | it easy for others to use In this course, we've already used |
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| 00:54 | and we were able to do a of things with turtles without getting into |
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| 01:00 | nitty gritty ease of how to do graphics and all of that. And |
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| 01:05 | because we were using the turtle So in general modules are pretty |
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| 01:11 | They allow beginners to do some, know, really seriously interesting things with |
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| 01:19 | because you just leverage somebody else's So you may not have the expertise |
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| 01:26 | do something like the turtles module or programming or whatnot, but you may |
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| 01:34 | able to use them and then in even build applications on top of |
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| 01:38 | not necessarily knowing exactly how to do lower details that are left to other |
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| 01:44 | . So that's the big idea. , in terms of the specific |
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| 01:52 | python module is just another file that py. It just contains definitions and |
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| 02:00 | that is used by other programs. , it's nothing, nothing else. |
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| 02:03 | just another python python program or a containing python code, python has a |
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| 02:13 | library that comes with a lot of that we can use in our |
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| 02:19 | Um to see all the modules you go there. They're all over the |
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| 02:24 | from math to random. That will today to what you can do on |
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| 02:30 | web, graphics and whatnot. There's lot of stuff there. However, |
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| 02:35 | all of it. In fact many those modules are not directly available for |
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| 02:41 | rune stone environment we use for learning . So if you grow beyond the |
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| 02:48 | we have here, you may need also grow into a more professional programming |
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| 03:00 | . So let's get the hang of do we use a module? First |
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| 03:06 | to use a module in your You have to have an import statement |
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| 03:13 | looks something like this. You have module called Turtle, you say import |
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| 03:18 | . And suddenly you have access to modules or all the codes in that |
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| 03:25 | in that module. All the work in that module. That statement has |
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| 03:31 | effect that once you've imported the module your program you can use total class |
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| 03:38 | screen class. So these are Total screen are special types with which you |
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| 03:47 | do special things. Remember the we know our strings into jails |
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| 03:52 | So those types are defined by what be inside that type and what you |
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| 03:59 | do with it like for integer, can do multiplication division addition and so |
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| 04:05 | . So these are a little bit types of classes you that are defined |
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| 04:10 | the module with which you can do interesting interesting things beyond those basic |
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| 04:17 | So once you've done in four title you have access to the turtle with |
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| 04:22 | upper testy class or type and screen or type. What can we |
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| 04:29 | Now we um make variables that are those types. The screen type and |
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| 04:37 | turtle type. And this is how do it. This is just a |
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| 04:41 | that we picked. WN and Mark our variable and Turtle was the module |
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| 04:48 | . And within that module. That , that the module defined is this |
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| 04:54 | . So once we have, once made the statements, we have created |
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| 05:00 | new objects or two new variables. is W N. Of the class |
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| 05:05 | type screen, other is Mark of type turtle. So, and once |
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| 05:14 | done with that type, you established imported the module, define your |
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| 05:20 | Now you can do all kinds of stuff again using the dark notation that |
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| 05:25 | use there where Now you can have statement like this. Mark is the |
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| 05:31 | type, you say mark, forward and it moves forward and you can |
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| 05:36 | it do all kinds of interesting things we saw in the turtles. The |
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| 05:41 | . Mark shoes before. Okay, is one example of a module. |
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| 05:50 | much more useful module is the math . The math module in python. |
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| 05:58 | in any other programming. Anything you need in terms of uh mathematical |
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| 06:10 | you're probably it's there in the math . So some examples here again to |
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| 06:18 | the math module, just like the module, you just say important |
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| 06:23 | And once you say important math, can say things like Math dot factorial |
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| 06:28 | . It returns the factorial if X an integer math dot log base 10 |
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| 06:35 | . Based on the algorithm of facts math dot sine X. That's the |
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| 06:40 | . No metric function returns the sine X in radiance. So there's many |
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| 06:45 | these functions and you just have to them and play with them. Um |
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| 06:51 | just not here that the usage in case is a little bit different from |
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| 06:59 | we saw with the turtle module. we're not actually defining new types. |
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| 07:05 | just makes these mathematical functions available to which perform a task and and return |
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| 07:14 | value. There is no need to any special object. Should be in |
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| 07:18 | even more internally that all you do math dot without a function. And |
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| 07:24 | this is when you say something equals dot, whatever your variable on the |
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| 07:29 | side gets that value. I think fairly straightforward. You just have access |
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| 07:36 | all these mathematical functions with the math . We will talk about one more |
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| 07:46 | in this course and in this which is the random module. |
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| 07:52 | first, a little bit of introduction random numbers in a lot of applications |
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| 08:00 | programs, you need random numbers because just a few of those examples if |
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| 08:07 | want to write some kind of a where somebody throws the dice. So |
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| 08:13 | the dice, it's basically generating a number between one and six. So |
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| 08:18 | need a notion of randomness. Same you are shuffling a deck of |
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| 08:24 | you know, one of those cards to show up, there are no |
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| 08:27 | cards. So you just use a number generator to generate one of those |
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| 08:33 | to simulate picking a card from a . And those, there are many |
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| 08:41 | beyond that for randomness. And if think about it, you can probably |
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| 08:46 | up with a few. Um one them, one example is modeling road |
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| 08:52 | , say you are trying to design um an intersection for a highway intersection |
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| 09:03 | intersection between two roads. And you're to say, trying to decide whether |
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| 09:09 | should be a stop sign or there be lights and if there are |
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| 09:13 | how long you know, lights should on or not. And then of |
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| 09:20 | you need some model of the road and the model of road conditions is |
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| 09:27 | to be that, you know, during the rush hour you can get |
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| 09:33 | between, you know, one car second to five cars a minute coming |
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| 09:40 | . So, but you don't have precise. They don't come uniformly distributed |
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| 09:45 | second every 10 seconds or every 30 . So you just basically pick a |
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| 09:51 | inter well saying, hey this car come in, when will the next |
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| 09:55 | come? It could be anywhere between seconds and a minute. Um so |
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| 10:01 | are other applications, real world applications random beyond the game. So it's |
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| 10:07 | fairly important function that we use. python of course provides a random module |
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| 10:17 | this and this is how it Like all the other modules, you |
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| 10:23 | access to anything in the random First thing you need to do is |
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| 10:27 | import it and then uh you have Um two things basically you can do |
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| 10:39 | it. One is to one of is to say random dot random. |
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| 10:46 | again, this is more like the module. You just say your variable |
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| 10:51 | random dot random and that will generate value between zero. A float value |
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| 10:59 | zero and one. Not including Okay, so this this this interesting |
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| 11:06 | says that the square parenthesis on the is saying that it's starting from zero |
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| 11:12 | zero is an acceptable value. The value is one but it has to |
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| 11:18 | less than one. The highest value up to one but not including |
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| 11:23 | So it generates a value between zero 2.9999999 whatever. And in case you're |
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| 11:32 | , you know, why do we it to that? If you think |
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| 11:35 | it, you can use this function get random values in any range? |
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| 11:43 | example if you wanted values between you zero and uh one million. You |
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| 11:52 | basically multiply the value you get by million. And now you suddenly have |
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| 11:58 | values between zero and a million. that is sort of the floor |
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| 12:04 | The uh the integral version of the function for random module is rand |
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| 12:15 | So again we're using the name Random is the name of the module. |
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| 12:20 | rand range will give us an The interrogator will be between the values |
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| 12:29 | and high. So generation an indigent this range. Again, not including |
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| 12:37 | same square here and the regular parenthesis . What that means is that if |
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| 12:45 | were trying to simulate throwing a dice would use something like this. So |
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| 12:54 | function will return one will return different but they'll all be either one or |
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| 13:07 | or three or four or five or . So that's about all we're gonna |
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| 13:14 | in terms of content will for you The focus this week is gonna be |
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| 13:20 | on on sort of bringing things into and getting more experience. Uh So |
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| 13:29 | things you can do yourself as examples to make yourself more comfortable with programming |
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| 13:36 | general and modules in particular we saw throwing a dice can be simulated by |
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| 13:44 | equals random door Rand range. Suppose want to write a program that wants |
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| 13:52 | verify if this is if the dice not loaded, which means is it |
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| 13:59 | returning numbers from 1 to 6 with you know equal probability. So one |
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| 14:06 | to do a quick crosscheck is that you call this modules many times 100,000 |
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| 14:14 | more and then average the score it , you can see if they're uniformly |
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| 14:22 | , what should be the average and uh When you throw the dice many |
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| 14:28 | and calculate the average, it may be precisely that but if the dice |
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| 14:33 | fair, it should be about in middle that is between 1-6. If |
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| 14:38 | of them are equal probability, the should be in the middle. So |
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| 14:43 | can try that yourself. Another simple to do to see if your table |
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| 14:51 | these modules and and the math function and random is to verify when you |
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| 14:59 | something and you take a square do you always get the original |
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| 15:05 | So one way to think of it that you know x minus square root |
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| 15:11 | X. Square, What does it you? So it should be |
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| 15:15 | But you'll find that in like in arithmetic, that's not always exactly |
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| 15:21 | So again you can think of a where you pick a random number, |
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| 15:28 | random value for X. But you to make sure you pick something that |
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| 15:32 | a legitimate angle number and then your and randomly and then take its square |
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| 15:46 | and then square red and then see you get and compare it to |
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| 15:50 | To see that if if for a several numbers that is correct, then |
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| 15:58 | you know, that means that you're correctly and the square root function and |
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| 16:04 | functions are implemented correctly. So those things for you to try and if |
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| 16:11 | have questions, you can always contact in short modules that you do seriously |
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| 16:19 | things even with a basic knowledge of . And that's why we want to |
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| 16:23 | them early. They're straightforward but very . So you should learn about them |
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| 16:29 | get used to using them. And not that hard to write your own |
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| 16:35 | . However, in this class, something you may want to do for |
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| 16:39 | , but it's not gonna be one the essential exercises and I will stop |
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| 5999:59 | |
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