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Let's talk about something that's very, very dangerous, and that is type conversion, it's something



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you should avoid, like the plague.



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Let's start with a variable called count now, you'd expect a variable called count to just be a number.



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However, there are situations like this that arise where you get a number as a string and not a number.



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Now, there is a way to actually convert these.



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You just say, I want to make an integer out of the variable count.



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Right.



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And now if I run that, that is going to work perfectly fine.



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And if you look over here, one is a string and one is now an integer over on the right side.



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So why do I say this is very, very dangerous?



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Well, let's have a very bad count.



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Let's say you're getting some survey data and by accident, hedgy skips and gets put in, maybe it stands



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for six gigabytes of data on the server.



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Now, your app doesn't expect that.



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So you're going to go integer.



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Go ahead and make that into a bad count and watch what happens.



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Absolutely nothing until I press the button, apparently we get nil.



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Now, what is, Neal, that means there is no value, because when you said I want you to create an



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integer from this, the system couldn't physically do it because there's a G in the way.



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Right.



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So there is no integer as far as it's concerned.



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So just puts nothing in now.



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There's no error here.



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Now, that's that's the tricky thing.



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If there was an error, you'd know because the whole thing would crash.



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But you're now going to be trying to use Knill where you are using other numbers.



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So if you added six to whatever it is, you'd actually be adding zero in the end.



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So that's why we want to avoid type conversion.



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There are times, like I say, where you have to do it because it's just the way things turn out.



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So let's look at the other way where it is fairly safe to do type conversion.



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Let's have a var my int equal to whatever seventy eight and let's turn that into a string because we



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want to display it on the screen.



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Now this.



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Is always going to work.



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Right, because if you go one way, so you're going from a more general variable, i.e. a no no, you're



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going.



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Let me get them to go back a second here.



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If you're going from a less general variable, i.e., a number onto a more general one is string or,



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you know, implicitly that all numbers can be converted to a string.



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Everything can be converted to a sentence.



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If it's an integer, a float, a double, it doesn't matter.



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But you also know that not all strings can be converted to an integer.



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So in this first instance, we tried to do strings to integers, which messed up the whole system because



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it just doesn't have the capability to create those.



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In this case, you can convert every number to a string.



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So in this case, the conversion is OK to do right.



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And it's actually quite a common one because when we display things on the screens of mobile apps and



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various softwares, everything gets turned to a string first before the user can actually see it.



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You don't actually print out an integer.



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It's always a string.



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OK, so that's when it's safe to do and in fact, you know, I'm going to put here.



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Unsafe.



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And safe now, if you're wondering what these are, these are comments to forward Slash's means, you



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can write some stuff that doesn't get interpreted, interpreted by the compiler.



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OK, so.



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Those are unsafe and safe conversions.



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Now, what are we going to do next?



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Well, I think I'll set you a little bit of homework.



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So what have I got here?



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Let's just copy it straight over.



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Do do create a double number over 2000 and then print that number to the command line, so you've used



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print before, you know how to make a double number, but there's a secret ingredient involving this



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lesson that you need to implement to make this work.