Python for Absolute Beginners Transcripts
Chapter: Code that interacts with users
Lecture: Concept: Multiple conditions to test at once
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We've seen if statements
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and we've seen wild loops, and we've also seen truthiness.
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But, what if you have two different conditions
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you have to test at the same time?
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So imagine you're writing a website
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and it's an e-commerce site.
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People have a shopping cart
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they can put stuff in the shopping cart, and then later
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somewhere you can tell them
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hey so and so, you have this many items in your cart.
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Well there's a problem
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you can really only have a shopping cart
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if the user is logged in.
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Because if they're not logged in
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where do you put their cart info?
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So we want to check both, that the user is logged in
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and that they have items in their account.
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So if they don't have either of those
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then we are going to do some else statements.
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So we'll say you have some number of items in your cart
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so and so, Michael Thor, log in
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and add some items to your cart.
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So we're going to get the user account
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which is a number, and we are going to get the user
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which is an object.
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It can either point at something or it could be none.
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Those are the two basic values you can have here.
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So we're going to test both of them.
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One, item count greater than zero.
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If we were sure it wouldn't be less than zero
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for some weird reason. We could just say item count with that truthiness table
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but lets be a little bit explicit here.
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Then we also want to check that the user is not missing.
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So we can just say user
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and then we combine these with various words
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the yellow here.
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We say and this means we want to check
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both, that they have items in the shopping cart
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and they're logged in.
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If it was sufficient that either of these were true
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then we could say item count or user right?
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It might just say you have zero items in your cart
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Michael, if your cart is empty, but you're logged in.
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Alright so you can use and, and or
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to combine these various tests
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into more complicated ones like this.
