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Hey everybody what's going on this is Caleb with Deb's Lopes dot com and welcome to your challenge video

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for the subjects section.

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We're going to go ahead and give you a challenge here to test your knowledge of subjects published subject

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behavior subject replace subject and variable so to do that.

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Go ahead and right click on one of the playgrounds and click new playground page.

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Name it.

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Challenge like so.

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Go ahead and select all and delete and you're going to paste in or type in import arke Swift.

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Import playground support but at the same time I'm just going to copy and paste it in here.

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There are the three lines you have been using and I have some comments here for your challenge for each

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of the subjects.

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Challenge one published subject.

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Remember that only shows elements pushed after the subscription.

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Your challenge.

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Create a public subject.

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Create a publish subject of type string.

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Subscribe to it.

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Printing the elements in the next closure and push in three movie titles using dot on next.

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After subscribing that is Challenge 1 challenge 2 is for behavior subject which remember that shows

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the most recently pushed element and everything after the subscription.

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Your challenge.

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Create a behavior subject of type double.

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Set an initial value of zero point zero zero.

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Create a variable an R X swift variable called bank balance of type double with an initial value of

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your choosing with an R subscribe to it.

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Adding the recently pushed item from on next to bank balance got value then pushed in the three amounts

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you are sorry then push in 3 separate amounts using on next.

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Finally print the bank balance value.

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This should show the bank balance with all of the values added up it should show your total amount of

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value after adding in 3 amounts.

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That is your challenge for behavior subject next.

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Replace subject.

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Remember a replace subject has a buffer size which is how many elements it can replay and it maintains

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a buffer of elements up to that size and will replay them to all future subscribers.

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So your challenge with replay subjects is to create a replay subject of type string called Twitter subject

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and you're going to set it to have a buffer size of three.

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Then subscribe to it and in the on next closure.

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Print out followed at and then print out the elements from your reply subject.

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Call on next 4 or 5 times on the replace object instance and pass in 4 or 5 individual usernames.

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Then create a new variable called new Twitter user and subscribe to Twitter subject in the next closure.

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Print out the last three values passed to Twitter subject.

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You should be able to do this with a reply subject.

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And finally last but certainly not least is variable k remember.

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A variable is a wrapper of behavior subject that works similarly to an ordinary swift variable.

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Your challenge create an instance of variable called full name and give it a default value of your full

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name.

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Then convert full name into an observable and subscribe to it.

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Inside the annex closure.

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Print out the name.

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This is your challenge for subjects I wish you luck and I'll see in the next section where we're going

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to talk about transformations.

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Cool things we can do cool functions we can call to modify data in a functional way.

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Very very cool.

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Nicely done with this section.

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Good luck with the challenge and I'll see in the next section.