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An unavoidable part of being a programmer is that your programs are going to give a lot of errors,

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you can't avoid bugs, you can't avoid programs breaking.

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A simple print function here with, let's say, a misspelled word with let's say no comma, if I run

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this, we've been seeing this a lot, right?

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We've been seeing a lot of this red throughout this course, a lot of these errors.

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If I tried to add one plus let's say.

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That works, but then all of a sudden I decide to add hello to one.

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And yet again, we see that red this time a type ER.

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That crashes our program like this is called an exception.

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And Python.

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Raises these exceptions whenever the interpreter says, hey, I have no idea what you're doing, something's

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wrong, I don't know what I'm doing anymore, I'm going to stop whatever I'm doing and I'm going to

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give you an output.

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This is bad because right now we're just playing, but if we're Google and people depend on us to maybe

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check their email, to watch YouTube videos, if our programs have exceptions and they stop working

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and they eera out, that's bad.

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That could cost companies millions.

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So how can we handle these exceptions that crash our program?

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Well, we need something called air handling.

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It's a natural part of being a programmer and a great programmer is able to handle errors in their program.

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Because instead of letting our programs just air, we're able to handle them so that if we get something

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like a type like this, we can actually handle that air within our programs.

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And in this section, we're going to learn all about that.

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But the key takeaway is that air handling allows us to let the Python script continue running, even

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if there are errors.

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Sounds pretty interesting, right?

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Well, before we get into that, let's just talk about some of the errors that exist in Python.

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We've already seen type error.

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Where are we trying to do something between two different data types that are incompatible, such as

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adding ENT and string and these built-In exceptions in Python?

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There's lots of them.

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And I'll link to this resource so you can take a look.

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But if I scroll through here, you see attribute, error and of failure, we keep going.

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We have a name error.

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We have so many error reference.

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There's just a ton.

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Let me just go through some of them that are quite common.

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One is a syntax error if I do def and let's say.

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Whoo hoo!

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And I forget a semicolon here and I run this.

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I get a syntax error, it's not a standard python syntax, I have to fix my error.

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I can also get something called a Namir if let's say I use one plus name like this and I click.

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Name like this, you can see the red underline here, I get undefined name so that if I run this code.

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I'll get a nightmare name is not defined.

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We've seen type ER.

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But what about this, what have we have a list, let's say Elai.

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One, two, three, and I access Elai, let's say an index of five if I run this.

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I get an index error list index is out of range.

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What if we had a dictionary, so let's say we're creating a dictionary here.

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We'll say a.

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Cause one and, you know, I will just leave it at that.

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So this will be a dictionary.

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If I do dictionary here and just try to access something that doesn't exist and I click run.

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I get a key error.

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Because I'm accessing a key that doesn't exist.

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We can also have, let's say, five divided by zero, which should give me a zero division error because

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I'm trying to divide by zero and well, you just can't do that.

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So there's lots of errors or built-In exceptions in Python.

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Now, you don't have to memorize any of these.

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Most of the time they'll come up in your program and you'll know what they mean.

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But you can always use this as a reference to read them.

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The question you should be asking yourself is, how do we avoid these?

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Because most programs aren't just us typing information, usually programs interact with the outside

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world.

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Right when I log into my email, I let a user use their email and password.

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When I play a game, I let a user control a character.

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So programs are constantly interacting with the outside world and they have to make sure that whatever

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input they get is the right type that they're expecting.

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Because if they receive something that they didn't expect like number and this number just happens to

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be, let's say, zero, that we give it.

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Well, this user broke our program, so we need to handle these situations where a user might give something

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bad that we wouldn't want.

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In the next video, we're going to explore how we can handle our errors.