Pass Cisco DEVASC 200-901 Exam in First Attempt Easily

Introduction

1. Software Development and Design

Hello and welcome. In this system, you will learn about data formats. You will learn XML, JSON, and YAML, and we will compare them. So what is the data format? When you are writing your applications or your code, you need to write in a certain way so that your computer will understand it. And when you're done with it, your colleagues will understand it, and you will be able to convert it from one format to another, so that you'll be able to format and change it for different applications. And your data formats are generally used by you to write applications and communicate with a range of APIs. For example, if you want to configure a Cisco switch, you have to understand what data types are supported by the API of that Cisco switch. And to deal with them, you need to know three of the data formats very well.

You will focus on some for certain devices; you will focus on some for certain APIs; but these three are the most important ones. So what are those? First of all, you will have the XML. XML is a little bit complex to use because it is generally for machine-to-machine communication. And when you are dealing with XML, it will be hard to read, and you will see different tags and different notations and syntax so that you'll be able to understand it. But it will be hard to read and hard to write. We will go over those tags in a little bit.

The next part will be about JSON. JSON is JavaScript Object Notation, and JSON is an alternative to XML. It is easier to read, and it is most often used for communication between a web page and a server. When you are dealing with JSON, the syntax is very important. The last one will be about YAML. And YAML stands for YAML and Markup language. Y. a. ML. And it is a good choice when you are choosing a data format to deal with your APIs because it is most widely used by nondevelopers, by people who are not accustomed to writing code in their day-to-day jobs, because it is readable and it is easy to use. and you will see that you are just writing a list. The most readable of the XML, JSON, and YAML trios, and what you'll be looking for, is whitespace. White spaces are important when you are dealing with YAML.

As you can see on the right, we have different formats with different syntaxes. When you are dealing with YAML, you need to care about the white spaces, such as these ones, and you need to care about those indentations. If you have two white spaces as an indentation, you will use it throughout your list. And if you just started with just one whitespace here and two whitespaces here, then you need to follow that because what you will deal with in YAML are keys and values, and they are just separated by whitespace and columns. Because JSON was derived from JavaScript, you are most likely dealing with a type of JavaScript programming language when dealing with JSON. And when you are dealing with JSON, you can convert JavaScript to JSON and JSON to JavaScript. JSON uses curly braces, it uses score brackets, and it also uses quotes such as these ones. And when you are dealing with JSON, you need to care about the syntax.

You need to ensure that all the syntax matches throughout your code. And each object starts and ends with a curly bracketlike diesel; just like we said in Yamo, white spaces are important, but this is not important with JSON. When you see any whitespace here, such as this one and this one, these are not important. However, if you see a white space like this one, a white space between first and JSON, this is significant because it indicates that the string contains a white space. It is not just dealing with syntax; you are not just dealing with the syntax anymore, and you will see that all values are just separated by a comma. And when you separate values with a comma, it is required for your objects, except for the last one, because we have other objects here. And when you are dealing with your JSON, you will not use commas at the end of a list of objects.

And lastly, we will deal with XML. XML just uses these tags a lot. These are tags. So if you're dealing with two, this is a tag. This is the sorting tag. And if you are dealing with a closing tag, you will see this notation, and you just need to use this slash notation to close the tag. And when you are dealing with tags, you have to be careful that the beginning and ending tags match up. If you're writing this as two, you cannot just write the closing tag as a capital two. You have to write it. If you started with small letters, then you'll write it in small letters too, and our version will also not work. If you started with capital letters, just using small letters as the closing tag will also not work. And in each tag, you are representing a completely different element. So you can also use the same tag in different places, but it will be a different element. So using tags is important because XML code heavily uses tags, and when you're dealing with them, you have to be careful about matching those tags.

So in this video, we went over three different data formats: XML, ESA, and YAML, and we compared them so that you will have a better understanding when you're dealing with them throughout the course. I hope this has been beneficial for you. Thank you for watching.

2. Lab - Installing Visual Studio Code

This course will use Visual Studio code. So to download that, you can just simply type "VisualStudio code" on Google and from there click on "VisualStudio code," and from here you will see whether you will download it for Windows, Mac OS, or Linux. For this course, I will use the Windows version, but you can use whichever version you want and it will work just flawlessly. So we will go and click on Windows Downloader, then we will just go and install it. After you download it and after you start the installation, you will see this in your own language, and you can click on the path where you will install it. You can go. Move forward. Then you will simply choose its name to move forward. Whether you want to put a desktop symbol on it or not doesn't matter. Let's just put one, and you'll be fine. And from here, you will just set it up. Click on Set Up, and you'll be done with the installation. After you're done with the installation, you will see this page. And now you have your Visual Studio code so that you can mimic my configurations on your own PC. Or you can just use it to develop code in JavaScript, Python, and any other language that Visual Studio code supports. On the left side, you will see the Start page and the Explorer part. You will see the search, you will see the recent, you will see the help page, and on the right, you can see the customized part and the learn part. When you click on here, you will see the Explorer page. And on the Explorer page, you can just navigate to the working directory, and you can click on "Open Folder." As our working folder, we've selected the Visual Studio code folder. And we can put our files in there so that our platform files can be placed. We can put our XML, JSON, and YAML files there so that we will be able to work with them, work on them, compile them on our Visual Studio, and deal with those quotes. And we can click on "New File" here and start a new file, let's say data formats. This will be our file for this lab. If you also want to save our data format file that I added some code to here, You can also save it by clicking on NewFile and saving it with that Pi, so that you understand it is a Python file. If you already know Python, that's great, and you will just get the benefits of it. benefits of knowing it. If you don't know Python, no worries. You can still go on and study Python. But this course will not be heavy on Python. You can just know it or you can just know how to read Python, and that'll be enough for you. Now, if you never installed Visual Studio on your PC, you will need to install some extensions, and it will give you some warnings in here. So you will install the Python extension as well as the Pilot extension, which will be Linter Pilot. And you'll see a pop-up here on the right, and you'll install Linter Pilot. It will be automatically installed. Lastly, you will also have the option of debugging, and you can go there and click on "Run Here," and you can start debugging the code, or you can come here to "Run" on the left hand side, and you can run and debug the code. If you have written the code in Python, if it is PY, then you will choose the Pythonfile option for the debug options, and then you will just start debugging in here. It makes no difference whether you click "Start Debugging" or "Run Without Debugging." However, you can assign a breakpoint so that the code will run until that breakpoint and you will have to step over and step into codes, and you can deal with those details later. But for now, it's important to just install Visual Studio and be aware that you can copy-paste codes in here and write codes in here so that you can parse them, whether they're in data format, YAML, XML, JSON, or whatever. However, you will be able to run and write code on this Visual Studio. So in this video, we went over how to install Visual Studio code on your PC, whether it is a Mac, whether it is a Windows PC, or Linux. And you've just learned how to get a Visual Studio code, choose your own operating system; we saw how to do it on Windows, and you'll be familiar with the visual settings of your Visual Studio code and the graphical user interface of Visual Studio code in no time. I hope this has been beneficial for you. Thank you for watching.

3. Lab - Data Formats and Converting YAML to XML

Hello and welcome. In this lesson, we will compare two data formats and learn how to convert from one to another. First of all, we will go over our YAML file, and in this YAML file, as you can see, it will be saved as the name and then AML. YAML. This is just like a shopping list; this is just like a user list; this is actually a list. So when you deal with them, first you will give them the ID. For instance, you will give the first name, and it will be in quotes, and you will see the same column here. And then you will see the last name, birth date, and address, and you can have two different addresses for the same user. and you will just deal with them by using white spaces. As you can see, you have one white space or at least two white spaces here, and you have two white spaces here, and you will see the same indentation in the same file. So you will not see three white spaces with different indentation in the same file. You will see the same thing over and over again. And as we mentioned previously in YAML, when you're writing code on YAML, you will just deal with the white spaces. You don't have to care about anything else. But white spaces are very important. In JSON, it was syntax; in XML, it was all about tags. And what happens if you want to convert the CMO to XML? You will see different formats; you will see different tools on the Internet, and I will show you one. But you should be able to convert it from one to another simply by using tags on XML. So if you put them side by side, you will see that you will just give the XML version under start, then you will give the user tag, and you will close the user tag here. And in between those user tags, you will just use the tags. For instance, for the ID part, you will use ID, then slash ID, and in between you will enter the value. And for the first name, last name, and birth date, you will use the same format. You will use the starting tag and the closing tag, and the closing tag will have a slash, and you can just convert the same thing. And you will use the indentations here so that you will be able to understand it better and see it much more clearly. But if you are dealing with the same address, you will see that they have the same tags, but the content is different. So you can do that in your XML. For instance, you can just use this online tool: online YAML tools from online Yamaltools.com.And you can put your YAML input on the left and get your XML output. For instance, if you just copy and paste the ID in here. Let's copy and paste it, and you will see that it is written via those ID tags. And when you copy the rest again, see the same thing. But what happens if you just delete one code? Then you will see the error, but if you connect it back to its original version, you will see that it is just converting it from YAML to XML. So you don't have to write in XML; you can just write it in YAML, and it will be converted to XML, as basic as that. So this is the importance of being able to compare data formats. You don't have to know it by heart, but you should be able to compare it. You should be able to understand and read it. As you can see now, I just copied the rest of the YAML code, and now we will see the XML part and XML format in XML format. And you can simply copy this code and use it as an XML output or as an XML code. And the only thing that you will do is just define the "find XML version" at the start of your code. So when you're dealing with your calls, whether it's YAML, XML, or JSON, you can even find JSON, converters, and JSON tools, and you can convert from YAML to JSON or JSON to XML. It will be very simple, and you will see many different tools on the internet, and you can simply use them, or you can simply write it in YAML and convert it by hand. You can also convert it by yourself, but using tools will be simpler if you are not doing this as your day job. So in this lab, you first went over how to write it in our Visual Studio code as a YAML. And we saw that we needed to deal with some columns, and we needed to deal with the white spaces on Yamo in particular. And on the XML part, you only need to deal with the tags and your tag IDs. So I hope this has been beneficial for you. Thank you for watching.

4. Concepts Of Test-Driven Development

And welcome. In this lesson, we will learn about test-driven development. Test-driven development is a method that software engineers or software developers use to write the test code before writing the actual source code for the actual production code. With the help of testing development, you test your use cases, and you will have some automated tests for your source code with this approach, and when you are developing your code, you will do those steps in iterations. So first of all, you will write your tests, and those tests should fail because there is not an actual code or a production code that will be helpful for you or that will help you pass those tests. When you write those tests, you will check what fails, but the real factor will be writing the tests that will fail and writing the tests so that you will know what you are expecting from your code. After seeing that those tests are failing, you will actually develop your code, and in this step you will write all the functionalities and all the code that you need to write so that all your tests that were failing will start passing, and after that you will see what is passing and what is not passing. If it is not passing, you will go and develop your code more, but if it is passing, you will go to the next step, and this step will be refactoring your code. In this step, you will refactor your code. You will discover certain parts of code that can be used multiple times so that you will need functions, which we will discuss, and you will also have better readability for your code and the design of your code will be greatly improved, and you will get a better design for your code as a result. Better readability. Your code structure will also be much improved. For your tests, you will check for expected inputs, and those will be the input parameters that will create some expected outputs, but you also need to check and test for unexpected inputs. Those will create some unexpected outputs, and they will create great opportunities to test your code for some unexpected ambiguities or omissions. When you are writing test-driven development software code and when you are using this software development method, you will have certain benefits and certain advantages. What are those? First of all, you will go with having a clear target to reach because as the test passes, you will see that your code will be better. will be improved, and when those tests are passed, you will have a clear goal because you will know what to write for. You will know how to make those tests pass, and you will know how to write. where to write and what to write. Another advantage will be avoiding ambiguities. During writing your code you might face with some bugs, some ambiguities, some omissions and before even writing your code. As you learn the tests and your unexpected expected inputs, you will avoid some potentially costly rewrites. Another advantage will be that it will be easy to debug your processes because you will even use some edge cases. You will even use some unexpected inputs so that your code will start passing. And as you will use those unexpected inputs and edge cases from the start, you will have a better and easier feedback process. Another step will be passing each test like a small victory, so you will have less to miss as you write your code to just make your test pass. You will have better estimates because you will know what to write for. And each step, each code part that will make a test pass, will be like a small victory for you, so that you will just improve your code one step at a time. And at the end, you will have a ready-made code. As you write your sofa with a tester in development, you will simply run the test and see that it fails. But you will know deep down what is making those tests fail, and you will completely be focused on making those tests pass. So this will be a very good method to get fast and actual production code, just by focusing on the important parts of your code and having a clear goal to reach and a clear target to reach, so that you will just be focusing on writing your code and what to write. So in this video, we went over testing and development, its advantages, its steps, and why we need it. I hope this has been beneficial for you. Thank you for watching.

5. Software Development Methods Part 1

Hello and welcome. In this lesson, we will learn about different software development methods and especially the software development lifecycle, which is a process that is used by software engineers. software developers to design. Develop and test high-quality software products, and while doing that, they will apply different methods; one of them is waterfall, another is lean, and lastly, we will also learn about agile waterfall, which, as you can see on the right, works just like a waterfall as a linear process, moving down through phases. In the waterfall software development method, you need to assume that all your requirements will be gathered upfront, and this will happen in the requirements phase. Once you are done collecting your requirements, you will then start with your design phase, and in the design phase, all of the information that you gathered in the requirement phase will be used to build a new, high-level design.

When you are done with your design phase, then you will start your actual purpose phase, where you will start coding You can also call this phase the implementation phase because in this phase you will implement what you need to write and code that, and after you are done with coding, you will just start testing and verifying what you quoted or what you implemented. You need to make sure that what you wrote or the code is actually meeting the customer's expectations. After you are done with the testing phase, you will go to the maintenance phase, and in the maintenance phase, you're having your customer use the product, and depending on the customer's feedback, you will make some changes to your system or to your code. We will have a couple of advantages and disadvantages, first.

When you are designing, you will see all the design errors and you will see many of the things that will cause problems later on, so it will be a better phase. And it will be better software development to see what can go wrong, and in this software development method, you must write good documentation that will be useful for later stages of your coding; you must also be able to measure your progress, and you can easily set milestones because the process is very rigid and structured, as you can see under a waterfall where the water simply falls down and the requirements are designed. Coding. Testing and maintenance will just follow up after you are done with this and everything. We will also have some disadvantages. What are those?

First of all, As a disadvantage you will see that you need together all the requirements beforehand and this will cause some problem because you need to get everything upfront and all the requirements should be collected and you need to decide however your design will be because you will get your currents according to that and in the very early stages of the project it will be very difficult to collect all the requirements and clients can change their mind about some features and some things that how your application is going to be delivered and also they will not know all the things that they want and as it will be very inflexible it will be very hard to just please the customer related with that and it will be very difficult to reengineer the application because if you went through quoting and then went to testing the customer will be in the process during maintenance so you will have some problems going backwards because in a waterfall it will be very hard to get the water from downhill to uphill and due to that you need to start your process from requirements again and go down below also you will see that your product will be shipped only at the end of the chain after testing and with that having no middle phases to test and nothing in between design and coding to see how the application will act it will be very lengthy process and you will see that you can face with many different errors and many different problems during the coding and testing so all in all this is a very old method.

This is like the 1950s method, and you will face many difficulties, so during those times, software developers and engineers just started using new methods such as lean and agile, and we will go and continue with them in the following videos. In this video, we went over the waterfall method I hope this has been beneficial for you. Thank you for watching.

6. Software Development Methods Part 2 Lean Agile

Hello and welcome. In this video, we will learn about Lean and Agile. First of all, Lean is actually one of the mostefficient way that is available to eliminate everything users. In the philosophy of Lean, if you don't need it, you just get rid of it, and when you are implementing this Lean process, you need to minimize your resources and, at the same time, produce consistent flow and profitability. When you are dealing with lean, you need to first get your people because people are actually the root of it all, and when you have the right people who can just go and get the results, then you will have some really nice outcomes, and this will depend on the responsibility of the right people. If you need people to continuously evaluate the valuestreams in terms of business processes and Lean processes, this is just what is happening in LIEN. And when you put people inside this Lean process you will need two more steps to get your trip ready. The first one will actually be your purpose, and when you're getting your purpose, you need to understand why you need to do a certain process and why you need to do it. You need to get your why, and after getting your why, you will reach your purpose and be able to complete your processes. So the last step will be your process, and this will consist of how your organization will ensure the steps will be followed. So these three things will just depend on each other. If you have the people and if you give them a purpose, then you will be able to get your processes right, and again, everything will turn into the good outcomes of your people. This is actually a Japanese philosophy, and this was applied after the Second World War to get the Industrial Revolution in Japan, and we all know the outcome of it. If we need something of good quality, it will be Japanese core. It will be something that is made in Japan, and the limb process just makes you do the right thing with minimum resources. When you apply this to your software, you simply get the right people and give them the right purpose, and if you put them in the right process, you will be very successful, and the outcome will be very profitable and consistent. Another software development method will be Agile. So we talked about how the waterfall is a linear process and how we can't just go back to the beginning and enter everything or how we can just put the water up front down to the lake or pond and just get and carry the water uphill. Start the process again, and this will not be a cost-effective process; this will be very expensive for certain areas, and it will be very difficult to implement it for the agile application process. You will use your feedback from the customer, and you will use short sprints instead of long runs. So first you will define your requirements, then you will design whatever you need to design, write your code, test it out, and you will continue maintaining it. But these will be short sprints. And for instance, this will be a short-sprint one. But if your customer needs something else, or if your customer wants to improve a certain process or a certain code part, then you will get another sprint and you will include another set of requirements in the design, coding, testing, and maintenance phases. At the end of each sprint, your team will just provide a shippable product, which will be delivered to the customer. So customers will have some feedback for you, and you will start your second sprint. Dealing with these feedbacks and requirements will entail changing some features and increasing capability. And during those sprints, you will have some daily meetings, and in the sofa development workspace, these are called as scrumps.So in Scrum, you will just define whatever you need to do on a certain day. And with its assistance, you will simply know what specific challenges you will face that day and discuss what you are currently dealing with. You will be able to evaluate potential challenges, and this will make sure that everybody is on the same page, and you will have a much more collaborative work environment. The advantage of Agile will give youa rapid and continues to open. So this will be very rapid because you will just use some sprints instead of long, slow walks, just as the word "sprint" defines. You will have a rapid process and you will continue to deliver so few releases. And thanks to Scrum, people will have great collaboration. And you will also be able to welcome some late changes, which will be welcomed, but you will also have some disadvantages. What are those? In this kind of approach, you will not have very good documentation because the main goal is not to juggle everything. The main goal will be to release new code. So this is a disadvantage when you compare it to waterfall, and without a complete requirement or a complete design, at the start of coding, maybe you will get some customer expectations that are not very clear, and you might also have a chance to experience scope creep. And this rapid development might increase your chancesfor some design changes in the upcoming sprint. So you might just write some code that will not be useful for the upcoming sprints. And you will need to change a lot between sprints. But all in all, this will give you the fastest software release cycle. And today, software development for Agile is the way to go for many different companies and many different software developers. So in this video, we went over the last two software development methods, lean and agile, and compared those with the waterfall, and also tried to understand why we need agile and why we are differentiating from the waterfall. We don't want to be rigid; we want to be flexible, we want to be fast, and we need to collaborate with the other developers as much as possible. I hope this has been beneficial for you. Thank you for watching.

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