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Convenience and it's are kind of in it's are useful for special cases.

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Imagine a situation where you have to initialize something but you don't have the arguments the way

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that you would usually have them you wouldn't have your name and email or a new ID or what not.

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Instead you have them in something like a dictionary or if you want to put some default values for whatever

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reason for those kind of situations we use a convenience.

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And it's not the only thing that's really important about convenience in it is that within the body

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of convenience it you have to initialize your object.

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Let's go ahead and see how we do that.

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I'm going to go to Scott start start your project on this fun going to Karlee convenience and it's

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my convenience in it.

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I have just like all the other times I have a class user and my class user has let's say only one attribute

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quality that name a string.

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And then I have one in it and in the end it's called input name string string which makes self name

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the com input name.

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Not if I want to write a convenience in it.

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This is what they should do.

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I should say convenience in it.

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And in my convenience and it's irrelevant of what you want to pass in as an argument.

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You must do this.

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You have to do a self in it.

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So I have to say self not in it one of these other ways of doing it.

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So I'm going to say solve it with No-Name for instance.

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So that's a convenience in it not you might be wondering.

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Well you're calling a method to call another method and nothing else is happening.

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Let me give you a practical example.

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Imagine you're reading some information from some backend and that can say they don't have any anything

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to do with classes or users or whatnot.

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Usually what you have in the back end is either integer or a string or an array or a dictionary for

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the most part and for the most part the important elements are arrays and dictionaries.

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So you have getting formations set in dictionaries or arrays and they don't know anything called a user

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for instance your user might be written in the backend like this.

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It might be that our user dictionary is going to be named the name key and that's going to be the name.

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All right.

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And they have another value let's say you I.D. She and that your I.D. key is a random set of characters

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so this is essentially what you get from your backend.

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You don't get a class coming from your back and you get information in a user dictionary.

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And now I want to use this information to produce new objects from my User class in a situation like

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that.

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And when I say Well give me a convenience in it it's an input dictionary which is of the type dictionary

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with a string.

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You could write a string on a string because we know there are strings or and when I say a string and

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in me just so that we can see more of the options.

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So my convenience any 3:13 put dictionary with these values so theoretically it would be like this erotically

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I would have remember this came from that.

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So now I'm going to say like my user is a user and which one I can use can I use it with the name or

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can I use a dictionary.

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So it's a lot better to use a dictionary one.

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I'm going to say dictionary and that is the use of the dictionary.

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So now I have a new user being produced by this dictionary and I have to do whatever I have to do inside

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my ends.

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So in my in it I'm going to say let's just call it the read the name to be.

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What is it going to be is going to be input a dictionary value for name she which I know it exists as

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what they want as with one does a string.

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The reason I need the as a string is because this is a need.

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I don't know whether the values in my dictionary.

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So that's one I'm going to call this one.

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Read you ID.

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And that's going to be for you.

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I d k as a string.

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And then when I'm initialising I'm going to say self in it the right thing and that's all.

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That of course in this example I'm not using my you ID if you want it it would actually add another

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one.

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So this is a you ID that's a string.

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It has to have an input ID and that must be a string string.

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I'm constantly making this mistake.

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Self-taught ID is going to be Impe with your ID.

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And then of course here we had to do this one as well.

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Say well that is going to be the read that you ID.

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So convenience us are used for situations such as this one.

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Our information for a specific cases are not being fed to us Devey that are in the talks in a way that

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we do whatever we have to do and then we call our in it is Slyne essentially is the most important aspect

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of a convenience any recording yourself.

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It based on well whatever you have in there.

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So that's about the convenience.

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It's a question that you might be having and that is for you if you're really perceptive at this level

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is up.

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Is this a safe way of assuming dictionary has a value called Name Key and it has a string.

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And to be honest no that is not a safe way of doing it.

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And since this is not a safe way of doing this what I'm going to do is I'm going to use God.

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So let's go ahead and do that.

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So you know I'm going to say God and what I'm guarding is this guy as optional a string.

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And this guy is optional a string.

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And if that was the case great if it wasn't the case return the net.

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Now let me quickly explain what happened in here.

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And you can see how it works.

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All right.

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I'm saying go for this two values.

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Read the name or read the name to be in put dictionary name key.

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If it did exist and if it was a string.

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So this idea will fail which takes us to the else or it will succeed.

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Which takes us to read you ID which does exactly the same thing.

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Either this succeeds finds a strange new idea and puts in the red your ID or it fails and goes in here.

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Now if we do end up in here if we do end up in the else we have to return and we have to say well this

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method failed if we couldn't do anything.

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Let's skip that for a second.

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Let's assume we did succeed.

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And if it did succeed it means that now we can go ahead and do a self in it.

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So in doing a search for it if we put the two values on we do everything as we used to do it before.

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Now here's an error in here that excludes telling excludes saying you can't return men.

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I'm assuming you need to work.

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No matter what.

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Only a failure will that it can return and which means your convenience in it should convert into a

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favorable one.

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There is a chance that it doesn't work so I'm going write this here.

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A failure will fail but in it it means there's something in it that it might actually fail.

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Otherwise it will work.

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So that's about that.

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With that in mind we covered a Class V in its inconvenience in its unfavorable convenience limits and

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we used it with the dictionary which is a very common practice when reading information from our backend.

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And with that we'll move on to our next lesson.