WEBVTT 00:00.050 --> 00:01.100 And just one more thing. 00:01.100 --> 00:07.100 Before we finish this Python section, let's talk about Python modules and see how to use them. 00:07.100 --> 00:12.650 So in Python or any other language you get a core set of functions and keywords. 00:12.650 --> 00:16.730 For example, the print function is part of the core Python functions. 00:16.730 --> 00:23.570 You can use the keyword def to create a function, etc. but this core base is somehow quite limited. 00:23.570 --> 00:29.450 If you want to connect to Gpio or start a web server or anything more complicated, you will have to 00:29.480 --> 00:33.950 write a lot of code all by yourself and this will take forever. 00:33.980 --> 00:38.540 That's why you can use libraries which are called modules in Python. 00:38.540 --> 00:44.990 The libraries contain a set of plug and play functionalities to solve a specific problem. 00:44.990 --> 00:48.020 Usually one library contains different functions. 00:48.020 --> 00:54.950 Later in this course we will use a Python module to use gpios, another one for the camera, etc. you 00:54.950 --> 00:58.550 can also have Python modules to do mathematics operations. 00:58.550 --> 01:00.920 Compute all kinds of statistics. 01:00.920 --> 01:04.250 Well, the number of possibilities is endless. 01:04.250 --> 01:10.290 And here I'm going to show you just one library and one function, you can get from it as an example. 01:10.290 --> 01:16.860 So let's say you want to make your program stop for one second, two second, whatever time you want. 01:16.890 --> 01:20.430 How to do that with just loops, conditions, functions and variables? 01:20.430 --> 01:22.200 Well, that's going to be very hard. 01:22.200 --> 01:24.660 So you can use the module called time. 01:24.660 --> 01:30.150 And with time you can make your program what we call sleep for a specific amount of time. 01:30.180 --> 01:32.730 How to import this time module. 01:32.730 --> 01:36.150 Well you have the import keyword you can see in Python. 01:36.150 --> 01:41.010 So you write import and then the name of the module which here is time. 01:41.010 --> 01:44.250 And just to test that we can just run this program. 01:44.610 --> 01:46.200 And you can see nothing happens. 01:46.200 --> 01:52.410 But if nothing happens if we don't have any error it means that this line was correctly executed. 01:52.440 --> 01:55.320 Now let's say I add a more letters. 01:55.320 --> 01:57.330 So this module doesn't exist. 01:57.990 --> 02:01.380 Now we have a module not found error okay. 02:01.410 --> 02:03.960 No module named with this name. 02:03.960 --> 02:06.780 So you can see if I just write import time. 02:06.780 --> 02:11.040 It's not doing anything because it's actually recognized. 02:11.040 --> 02:19.550 And then in this module time we have a function called time dot sleep, and I can put a integer, for 02:19.550 --> 02:20.870 example, or a float. 02:20.900 --> 02:23.870 I can put one second like this as an integer. 02:23.900 --> 02:25.070 It would also work. 02:25.100 --> 02:29.450 This means that I'm going to make the program stop for one second. 02:29.480 --> 02:32.420 That can be very practical if you want to measure. 02:32.420 --> 02:35.540 For example, I'm coming back to this temperature sensor example. 02:35.540 --> 02:43.010 If you want to get one temperature every second, then you can just use this function here between every 02:43.010 --> 02:44.300 sample that you get. 02:44.300 --> 02:48.980 And just to give you an example, I will print a like that. 02:48.980 --> 02:53.900 And then I will print B after like this. 02:53.900 --> 02:57.980 And if I run let's look at what's happening here on the shell. 02:58.010 --> 03:03.650 So if I run that you have a and then you have B but not immediately okay. 03:03.680 --> 03:06.350 B is coming one second after a. 03:06.380 --> 03:06.680 All right. 03:06.680 --> 03:12.320 So that's one example of one module that we import with one function that we use. 03:12.320 --> 03:18.020 And as we progress with the course we are going to use many more modules that will allow us to use cool 03:18.020 --> 03:21.170 functionalities with Python and the Raspberry Pi.