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Welcome back, my friend.

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Welcome to another lecture's show.

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Before doing anything else, I just want to fix our form.

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So when I say for my money, I'll fix the forum.

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The way we submit things, it's like here.

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So if I don't if I click enter now or the whatever, you click on the mouse because we have to event

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listeners.

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It will work for both of them.

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Yeah, but the thing is that look at what we are doing.

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We just having and actually this part, everything else is empty.

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No.

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Also the calories and the quantity are strings.

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So even if I had here food one hundred and fifty and I just just want to show you something, there

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will be still um still considered as string's.

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So we need to change this one.

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By the way, you can change this here.

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You can put a placeholder where it is.

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It is placeholder one.

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Right.

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And before we didn't have any placeholders but that is considered a string.

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You still need to manually insert one, right?

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Yeah.

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What we can do here, we can just put a negative number in minus six point, I don't know, description

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for it.

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It will still work.

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So we don't want this to happen in our application.

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We don't want a negative values.

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We can restrict it through this form here.

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But I just want to do it through JavaScript.

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Right.

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So let's change it where we get this.

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When we are getting here now, we have two things that we need to change.

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We getting the calories and a quantity.

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And I want the calories to be considered as float's as a decimal.

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Right.

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And there is a function called Parslow that we can use it here.

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And that function passes this part here that that returns a string and returns to a floating point number.

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So we just need to do one line pass float and put this one inside of these brackets and save it.

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Why?

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Again, because calories, I just want to have decimal number like seventeen point eight, for example.

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Right.

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And look at what's happening now.

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It's not not any more string.

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It is proper number.

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So the first float returns.

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So this function pass float, the partial function passes a string and returns a floating point number.

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Now, also, there is a one more function here in here.

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We're not going to put one point one.

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That's not going to happen because we can't eat.

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For example, we can't say, OK, half a burger.

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That's maybe you can, but in my case, that doesn't make any sense.

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So I just want to have a real number or integer.

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So there's a function called Pass in and I'm going to use it here in this pass in function parses of

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string and returns as integer.

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So let's save it.

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Yeah.

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Let's go back here and let's say, OK, food one in one hundred and fifty two point or point three.

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So now I do have these hundred fifty two point three and this as a no it's not string anymore.

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So you can see how easy it is to change from a string to a number and we are returning that this object

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with those values.

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So there's nothing, nothing special about this, but it will save a huge time for us in order when

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we save this where we store this data somewhere in that with this add calories function, we need to

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do something.

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Now, also, what I don't want to happen is I want to have this here negative value.

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I don't want to happen.

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Right, because here it oh, now it's working and we don't have any way to stop it.

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So where we can stop this one.

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So here I'm cancelling lock the get form input and that is from this function here result.

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Right.

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The object.

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But what we can do, we can just create some if condition here and we can check if get form input for

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example.

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So what we can check here is if that description is not empty.

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Right.

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It's not empty string because the description is a string.

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So let's test it out and I'm going to wrap this one in here.

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I'm going to say ls council and you can say you have empty description.

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Feel right.

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Just to test it out now, let's see what will happen.

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So if I click now enter, I do have only deselect this manually, but you have empty description feel

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right.

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But if I do enter here, food, everything else, it's not there.

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And we don't have values here, but it's still we're going to work because we are just checking for

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the food, ok.

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Anything, not a number.

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Any end means not a number and we have a little function for that to check.

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So I'm going to I'm going to tell you that is any and there is a function call is.

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But here we need to concatenate and and say is an eight and so is any method determines whether a value

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is an or not a number.

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So this method returns.

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True.

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If the value is of the total number and equates to not a number, otherwise it will return false.

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I know that's a little bit confusing.

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Well, let's test it out here in the console and I'm going to show you.

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So let's make it bigger.

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And what I want to do, what I want to say here is anyon.

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And I'm going to pass here a number and this will return false.

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So it's an end method determines if the whether the value side is not a number.

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Right.

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And this is actually a number.

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This matter indeed is true.

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If the values, the type of numbers.

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So what we can do, we can just put this one.

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Let's just test this one.

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One more thing.

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And if I put here string, what do you think will happen?

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It will return.

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True.

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So I want this function to change it in every time I have a number to be true.

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Right.

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So how can I do exclamation mark?

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And so I negate is anything and when I put no now it will return me true.

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And when I put a screen now it will return me false.

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Right.

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So whenever I put here, it will return false if it's not a number, right?

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So that actually returned.

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True, but I just want to have so by the way, here, we will not be able to put a string just I'm just

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telling you some pressing SDF so we are not able to put a screen.

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Why?

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Because in the index I do have this type number and in that browser in Firefox or in Google Chrome,

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it is working like that.

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It's not allowing you to put a string here.

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That's one way you can make this application it.

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So it's not a number in what we can do here.

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We're going to say get for input, not calories.

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Right.

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So let's see if that will work.

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Now, just going to remove this one here and remove everything.

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And I'm just going to put a food here.

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I'm going to click enter.

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You have empty description, fill in.

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Why is this happening?

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Because here here I don't have this one now, 15.

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Now it will go any inside will enter.

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So I do have you have an empty description fill and I'm checking two things here.

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That's why to go there, because one of them was not was not a number was actually an empty string.

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So if I go back here, it will you have an empty so we can change it.

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You have an empty fields.

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Or make better, let the better do this so you can say, please feel the form correctly, but we're

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going to remove these Ellspermann, please feel the form correctly.

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Like that and make it A, B, C, so now it will not go there.

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Please fill in the form, collect correctly food in calories.

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How cool is this?

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They're working now.

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I need to check one more thing here.

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If I put a zero, it will still work.

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Right.

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And I don't want that to happen.

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So what I can do, I can check if the get for input calories is bigger than zero.

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Right.

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That will fix two things.

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It will fix the negative values that we can enter minus and it will fix if it's zero.

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So I'm just asking these value to be bigger and positive.

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Right.

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You know, I save food, click, enter.

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It's working.

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Let's try with minus should not work.

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Please fill in the form correctly.

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If we put a zero areas he's saying to here it's not working.

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OK, so we fix a couple of scenarios here.

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We need to do this one.

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Right.

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We're not worried about the selection because it's already been preselected.

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He's been selected to add.

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But if you have a preference to do the burn, just cut this part here and put it here and every time

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you will be selected the burn part.

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Now, one more thing we need to do, we need to check for.

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I'm just going to copy this one.

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I'm just going to copy even with that and operator so now get put quantity.

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OK, not should not I should not go there.

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So I should go here.

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Quantity.

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Better to make it like this, and quantity should be bigger than zero as well.

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OK, no, let's just it that when I click here.

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Please fill the form food again.

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It's not working.

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Just the calories.

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It's not working.

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Put here one and it will work.

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Now I do have like just test it out.

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If I put zero will not work.

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If I put minus one still it will not work.

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So now the form is super secure.

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I mean it's not secure.

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It doesn't allow us to to get input.

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That is not valid for our calculation.

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For example, I'm not being able to put minus 150 calories.

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Right.

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Because that means that I'm going to burn and I should select this and I should again put a positive

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number, because after that, we will subtract that number from this total here.

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Right.

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So that's pretty much it for this lecture.

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What we have done, I'm just going to be super, super quick.

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So we use Borislow and pass in to convert that string to an integer.

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That's why we have this now.

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A hundred and fifty and this also.

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The add calories where it is in the add calories, we did check in this function if the description

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is empty, if this is a number.

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So if it's not number eight, that's why this sign is here.

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Operator, otherwise, if it's greater than zero, so we get rid of that negative values and zeros and

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we have done the same thing for quantity.

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Now we can take care for the rest of the hour.

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Logic in that, do something with adding calories.

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So I hope you enjoyed this lecture.

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It wasn't something special, but we just still managed to do a couple of things that will make a bucks

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in future.

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We will have to do them in future.

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So thank you very much.

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And now we'll see you in the next one.

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Also, we're not going to use this one that was just for testing.

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You can comment out or you can delete that one.

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Right.

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So I'm just going to delete and maybe in future I'm going to show you something.

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For example, if you want to get here some message, you can write message.

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And after after we finish this project, you can put your div with a with a class message.

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And when the form is not good, you can just display that one.

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Right.

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Which you can select with a selector, but that is for your for you to do after we finish this project.

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Right.

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Because it's not going to be complex, because you can learn a lot of things and you will know how to

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do them.

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So thank you very much and I will see you in the next one.