WEBVTT 00:00.080 --> 00:02.120 Well, we have a huge day ahead. 00:02.160 --> 00:03.720 Welcome to week one. 00:03.760 --> 00:04.640 Day four. 00:04.680 --> 00:05.640 This is the day. 00:05.640 --> 00:08.800 It's the second yellow day of digging into integrations. 00:08.800 --> 00:11.560 But in addition we're also going to talk about data. 00:11.560 --> 00:15.200 And we're going to look at expressions at least at a high level. 00:15.200 --> 00:16.120 Let's get into it. 00:16.120 --> 00:22.400 So largely in NHSN, data is something which is described using this format called JSON. 00:22.560 --> 00:28.000 And I imagine that at least half of you, you may fall into the half that are very familiar with JSON. 00:28.040 --> 00:30.160 You've possibly some of you have just seen it before a lot. 00:30.240 --> 00:34.880 Some of you actually probably JavaScript people that know it back to front, and some of you may be 00:34.880 --> 00:35.280 new to it. 00:35.280 --> 00:38.640 You've probably seen it, but you may not know that much about it. 00:38.640 --> 00:40.320 I'm going to cover it briefly. 00:40.320 --> 00:43.480 The main message is you will get very familiar with this. 00:43.480 --> 00:45.000 You're going to see it a lot. 00:45.200 --> 00:52.400 JSON is this very simple, standard way to describe structured data in a way that happens to also be 00:52.440 --> 00:55.080 sort of human readable, which is very convenient. 00:55.080 --> 00:59.400 So machines understand it, humans understand it, and we can work together with it. 00:59.560 --> 01:03.560 Let's cover the four basic ingredients of JSON. 01:03.600 --> 01:06.150 And if you know all this already, just put me on two x axes. 01:06.150 --> 01:07.110 Zoom through this. 01:07.110 --> 01:10.590 So first up, Jason is a way of describing data. 01:10.630 --> 01:16.670 Fundamentally, it expresses things as key value pairs, which means that everything has a name and 01:16.670 --> 01:17.310 a value. 01:17.750 --> 01:23.670 The pair could be a person might have a first name and a value, a last name and a value, an age and 01:23.670 --> 01:24.190 a value. 01:24.430 --> 01:30.510 These are examples of key value pairs, and that forms the heart of Jason and these values. 01:30.550 --> 01:33.790 They can be bunches of text which are called strings. 01:33.950 --> 01:35.150 They can be numbers. 01:35.430 --> 01:37.910 They can be booleans which means like true or false. 01:38.110 --> 01:39.910 And it can be a few other things as well. 01:40.350 --> 01:45.110 So the second key ingredient of Jason is called an object. 01:45.110 --> 01:48.550 An object is basically a bunch of key value pairs. 01:48.710 --> 01:49.710 It's a ton of them. 01:49.750 --> 01:54.190 There could be a person object, which means there might be a first name, last name, age, and other 01:54.190 --> 01:54.710 things. 01:54.990 --> 01:59.230 There's another name they're sometimes called dictionaries and dictionary will be familiar to people 01:59.230 --> 02:02.310 from a Python background because it's like a Python dictionary. 02:02.510 --> 02:08.390 Uh, so that is known as an object, a bunch of key value pairs, or maybe a bit more, as we will see. 02:08.430 --> 02:14.500 And the next ingredient is called an array, Ray, which just means an ordered list of things. 02:14.900 --> 02:17.100 And then the final one nesting. 02:17.100 --> 02:24.420 This is to say that a JSON object we've already said it can contain strings and numbers and booleans. 02:24.660 --> 02:32.780 It could also contain other JSON objects, and those JSON objects could also contain objects and lists 02:32.780 --> 02:33.780 of objects. 02:33.780 --> 02:40.060 So you could have some JSON object that is composed of lots of other objects, which themselves are 02:40.060 --> 02:41.580 composed of more objects. 02:41.580 --> 02:45.340 And a lot of this will come together when we see some concrete examples. 02:45.340 --> 02:49.740 And just to say a couple of words about each of those, and even for those that for which this is this 02:49.740 --> 02:52.660 is old hat, I hope to say a few more interesting things. 02:52.660 --> 02:54.220 So key value pairs. 02:54.420 --> 02:57.220 All data is represented this way in JSON. 02:57.340 --> 02:59.580 It's like name and then a colon. 02:59.580 --> 03:00.620 And then Alice. 03:00.740 --> 03:03.180 It's a key colon a value. 03:03.420 --> 03:09.820 Or it could be age colon 30 or it could be colon false. 03:10.180 --> 03:12.740 And it could also be middle name colon null. 03:12.740 --> 03:14.660 So there's a few things to point out here. 03:14.700 --> 03:20.930 The first of them is that whenever you have strings text, you put double quotes around it like you 03:20.930 --> 03:21.290 see here. 03:21.330 --> 03:23.290 Like name and Alice have double quotes. 03:23.330 --> 03:25.210 Numbers do not have quotes. 03:25.210 --> 03:27.970 They are just numbers as it appears there. 03:28.410 --> 03:34.410 Uh, you could also see that that uh, booleans, trues and falses, they come as true and false in 03:34.410 --> 03:34.970 lowercase. 03:35.010 --> 03:37.010 Like, you see, they're false in lowercase. 03:37.050 --> 03:39.970 People from a Python background are used to it being a bit different. 03:39.970 --> 03:43.090 This is what it is in JavaScript, in JSON. 03:43.410 --> 03:47.970 And then that last one, null is a special thing that you're probably familiar with. 03:48.010 --> 03:49.570 That means kind of empty. 03:49.850 --> 03:53.290 And that is also a value, an acceptable value. 03:53.610 --> 03:55.210 So just a few things to point out. 03:55.250 --> 03:58.370 First of all, you need to use double quotes, not single quotes. 03:58.370 --> 04:00.410 And that's a little trap to watch out for. 04:00.610 --> 04:02.570 Uh, and also not curly quotes. 04:02.570 --> 04:07.930 If you type something in in many word processors, it will automatically convert your quote marks into 04:07.970 --> 04:12.530 curlies to go around the the words, and that will cause problems in JSON. 04:12.570 --> 04:14.610 They have to be straight up single quotes. 04:14.930 --> 04:22.480 True and false are in lowercase, and it's best practice when you have your keys to not have a space 04:22.480 --> 04:27.320 in your key, but to use something like the you see, I use the underscore here instead of a space for 04:27.360 --> 04:28.280 is student. 04:28.320 --> 04:29.760 Now it's actually allowed. 04:29.760 --> 04:35.240 You can have spaces in keys, but they tend to cause a few problems in various ways. 04:35.240 --> 04:37.600 That means that it's probably not worth the trouble. 04:37.640 --> 04:42.520 Better not to have spaces in the keys as a general principle. 04:42.560 --> 04:43.640 Okay, so that's number one. 04:43.640 --> 04:45.360 Key value pairs okay. 04:45.680 --> 04:47.640 Secondly, the object. 04:47.760 --> 04:51.800 So an object represents a thing with a bunch of key value pairs. 04:51.800 --> 04:55.040 And the way you write an object is using curly brackets. 04:55.080 --> 04:57.280 Curly braces as are sometimes known. 04:57.280 --> 05:00.680 So you open a curly brace it means okay I've got an object for you here. 05:00.680 --> 05:02.240 And then we have a key value pair. 05:02.280 --> 05:07.600 The name is Alice, and that comma at the end signifies that there's another key value pair to come. 05:07.720 --> 05:09.320 And it is age is 30. 05:09.360 --> 05:13.000 And then a comma there's more is student is false. 05:13.000 --> 05:15.760 And then a comma middle name is null. 05:15.760 --> 05:18.360 And then no comma means end of object. 05:18.360 --> 05:20.160 Close curly braces. 05:20.360 --> 05:22.880 And we are done defining this object. 05:22.920 --> 05:23.440 Okay. 05:23.480 --> 05:24.720 And just a few things to note. 05:24.720 --> 05:29.870 First of all, it's common to write it this way, with this kind of white space, with the things indented 05:29.870 --> 05:34.550 like this, so that it's really easy for humans like you and me to look at this and, and see what it 05:34.550 --> 05:38.390 means that it's an object, but it actually doesn't matter for the machine. 05:38.390 --> 05:41.910 You can choose to indent it and space things out with empty lines like this. 05:41.910 --> 05:43.550 Or you could write it all on one line. 05:43.550 --> 05:44.590 It's the same thing. 05:44.830 --> 05:50.670 And also, as I mentioned, it's it's worth noting that that last element there must not have a comma, 05:50.670 --> 05:51.830 that last key value pair. 05:51.950 --> 05:53.150 And again that's a difference. 05:53.150 --> 05:57.630 Some people in other programming languages, if you're Python, then you know that it's fine to put 05:57.630 --> 06:01.270 a comma at the end of the last entry, but not with JSON. 06:01.430 --> 06:01.710 Okay. 06:01.750 --> 06:02.950 That's number two okay. 06:02.990 --> 06:04.430 Number three is an array. 06:04.550 --> 06:05.990 And you probably know this. 06:06.150 --> 06:09.590 An array is something which has square brackets around it. 06:09.590 --> 06:13.630 So this would be an array of three fruits apples bananas oranges. 06:13.790 --> 06:16.830 You have an element and a comma another element comma another element. 06:17.070 --> 06:19.310 And here's here's another array. 06:19.350 --> 06:22.350 This is a series 11235 if you know what that is. 06:22.670 --> 06:23.910 And you can also mix. 06:23.910 --> 06:28.030 You can have numbers and booleans and text strings in there if you wish. 06:28.030 --> 06:29.190 That's another array. 06:29.390 --> 06:31.470 And you can write arrays like this. 06:31.470 --> 06:32.860 And sometimes people do. 06:32.860 --> 06:35.220 And so that would also make a good array. 06:35.420 --> 06:37.700 An array you can think of as like a value. 06:37.700 --> 06:39.420 So an array can be the value. 06:39.420 --> 06:43.660 If you have a key value pair, you could have something like favorite fruits as the key. 06:43.700 --> 06:46.420 And the value might be apples, bananas, oranges. 06:46.420 --> 06:50.260 That would be a good value for the key favorite fruits. 06:50.460 --> 06:58.580 And then finally, just to explain again that that it's it's fine to have things like lists which contain 06:58.780 --> 06:59.620 objects. 06:59.620 --> 07:04.500 So here's an example of a list which has two things in it two things and they are each objects. 07:04.500 --> 07:09.860 The first one is an object which has a name Alice, age 30, in blue there. 07:09.860 --> 07:13.340 And the second object is name Bob, age 35. 07:13.340 --> 07:18.180 And these are two different objects that are part of the array that I'm showing you there. 07:18.460 --> 07:22.900 And you can also have you can write it like this as well, which, which is a bit nicer, which is just 07:22.900 --> 07:27.060 to show that it is a array with two elements. 07:27.060 --> 07:29.220 The first one is Alice, the second one is Bob. 07:29.620 --> 07:34.420 And then similarly an object can contain other objects. 07:34.420 --> 07:35.740 So here is an object. 07:35.740 --> 07:37.370 This is some sort of an address. 07:37.370 --> 07:42.650 It has a street, a city and a country as three different keys in this object. 07:42.930 --> 07:46.170 And what we could do is we could have this object. 07:46.170 --> 07:47.210 Check this out. 07:47.210 --> 07:54.410 This is a single object, and it is something which has a name, age and address as three different 07:54.410 --> 07:59.330 keys in this object and that address key, the value for address. 07:59.370 --> 08:01.690 It's not text, it's not a number. 08:01.690 --> 08:02.570 It's not an array. 08:02.570 --> 08:03.610 It's not a boolean. 08:03.770 --> 08:06.290 It is itself an object in yellow. 08:06.290 --> 08:08.890 In fact, it's the same one as I put in the box above. 08:09.010 --> 08:14.970 It's that object which has street, city, country that is a smaller object, which is part of the bigger 08:14.970 --> 08:18.410 object which contains Alice and her age. 08:18.690 --> 08:25.370 So that gives you just a sense that objects can be made up of other objects, and of course also of 08:25.370 --> 08:25.970 arrays. 08:25.970 --> 08:28.570 And if you knew all this already, then congratulations. 08:28.570 --> 08:31.530 If you didn't, then hopefully this gave you just a bit of intuition. 08:31.570 --> 08:35.010 Don't worry about it, because we're going to see so much of this, it will become second nature. 08:35.370 --> 08:39.250 Just to give you some some of the lay of the land before we dive in. 08:39.650 --> 08:40.370 All right. 08:40.410 --> 08:42.770 Next up we're going to talk about expressions.