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All right guys, it's time for the final hurdle
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before we get to our goal post. In this lesson,
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I want you to switch over to the final hurdle challenge, which is hurdle 4.
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And in this particular version of the hurdle,
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the wall that the robot has to jump over to now has a variable height.
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So the height of each of these hurdles is completely random,
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the position of the hurdles are random
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and also the number of hurdles is also going to be random.
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You can see that every single time that this regenerates,
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it comes up with a completely different set of hurdle profiles.
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And now we can't just jump because we don't know what the height will be each
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time.
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So we have to use what we've learned about while loops to modify this jump
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function and see if we can get the jump to jump as high as necessary
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depending on the height of these walls. Just as a reminder,
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in order to complete this challenge,
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you should take a look at the Reeborg's keyboard window and go to this tab called
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conditions and see that you can check if the front of the robot is clear,
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if it's right is clear, if there's a wall on the front,
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if there's a wall on the right and various other things.
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The ones that are probably going to be the most useful is this top row here.
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So I want you to take a look at these conditions,
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see how they're spelt and how you can use them,
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and then try to use them and test them out using your Reeborg robot.
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Now, the goal is of course
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to reach this final flag going over various hurdles
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using this dotted line as the path, which is going to be different each time.
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Just as a head up, this is going to require you to modify this jump function.
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Have a serious think about it because it's not easy
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and you're going to need to use more while loops to achieve this end outcome. And
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try to see if you can solve this challenge in the least lines of code possible.
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So I managed to do it in as little as 24 lines of code,
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so see if you can aim to achieve that.
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Pause the video now and give this challenge a go.
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Right?
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All right.
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So the key difference between this particular hurdle and the previous version is
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that the height of the wall is now random. Instead of just jumping over one
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square, where we turn left, move, turn right, move, turn right move,
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we have to now see if the right side has a wall,
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or if it's completely clear. Now, in this case,
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what I want to happen is I want to turn my robot to the left first of all,
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and then I want to check if there is a wall on the right.
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So I can use this condition wall on right to achieve this.
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And if that is true,
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then I want to continue moving forward until there is no longer a wall on the
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right, in which case I'm going to turn right turn right
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and then start going down. So let's modify this jump function.
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We definitely need the robot turn left, but after it turns left,
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we're going to use a while loop to say that while there is a wall on the right
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then in this case, we're going to move forwards.
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So we're going to go up in this direction basically
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because we've turned left already.
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Let's test this out and let's run this code.
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You can see in this version of events,
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my robot is going to keep going until the very end of the screen.
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This is not what we want.
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So what we want to do is when this is no longer true,
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it's going to skip to line 10. So at this point,
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there is no longer a wall on the right,
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because otherwise it would have continued looping and calling this line 9
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where it gets it to move forward. When there's no longer a wall on the right,
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then we want to do what we did previously
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which is to get our robot to turn right move,
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and then turn right. Now at this point, we have to move down the wall.
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And what we're going to check is whether if the front is clear,
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because it's only when we reach the very bottom here, when the front is blocked,
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do we actually turn left again and continue back to our while loop here to move
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forward. To do this we're going to add yet another while loop.
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And in this case, we're going to use the front_is_clear condition.
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While the front is clear,
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we're going to get the robot to continue moving forward.
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So once it's turned to face this direction, and there's no wall in front,
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it's going to keep going until this is no longer true.
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And that is the end of our jump.
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So now we've basically modified this jump function to take into account all of
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these new things such as while there's a wall on the right
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then continue moving upwards, while the front is clear when it's coming down
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then continue moving downwards. And then at the very end,
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we're going to get our robot to turn left so that we're ready to go and check if
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we're at the goal. And if we're not at the goal,
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then we're going to check if there's a wall in front,
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if there is a wall in front that we're going to jump,
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otherwise we're going to continue moving forwards or rather to the right to get
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to the goal. So now this is the final code.
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And depending on the number of spaces you've added in here,
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obviously it's a little bit easier to read if you actually have it like this.
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But depending on how you've spaced things out in your code,
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you should end up with anywhere between say 20 to 24 lines of code.
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So I want you to be able to see all of these lines of code on the right when we
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run this code.
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And I've actually got a typo in here that it's going to tell me.
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So it's going to say invalid syntax
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and the problem is just because I forgot a colon here. If you get that
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pop-up invalid syntax
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be sure to check if you have any problems in here and it can get a little bit
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complicated if you leave your code for a long period of time before you test it.
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So test your code after every little iteration
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and then when you actually get something like an invalid syntax,
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you'll be able to catch it more easily.
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So now let's go ahead and regenerate our map and let's try it again.
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So when we're going to make a jump and then we're gonna turn right,
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and we're going to keep going down until we hit the wall and we turned left,
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and now we're not out the goal, and there's still a wall in front.
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So we make another jump and we go down this much, much larger wall.
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And then we continue this process of using several while loops,
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checking if there's a wall on the right, checking if the front is clear,
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checking
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if there's a wall in the front in order to achieve our goal and get to our final
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destination. Now for your code to successfully complete this challenge,
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the line that your robot draws should follow the line that started here,
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just like what you see here.
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So instead of going just over the top and getting to the final goal,
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it should follow each of these steps and finally
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you should get that green pop-up where it says it's at the right position.
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So did you manage to complete this challenge?
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If not, be sure to review the lesson on while loops and just have a play around
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with while loops.
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Try some of the different conditions and see what happens when you run the code
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and see how the robot behaves so that you get a good grasp of how these things
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actually work.
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Now on the next lesson is our final project and we're going to get our robot to
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be able to navigate a maze all by itself using what we've learned
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including functions as well as while loops, as well as using good indentation.
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So for all of that and more, I'll see you on the next lesson.