Fruit Transcript

Start visual description. The instructor’s screen is shared where he shows how to prepare and write code for a particular program. He demonstrates the steps as he describes each aspect. The instructor can be seen in the top right-hand corner in a small box. End visual description.

[00:00:00] Instructor: Hey, let’s go through the “You already said that…” activity. So what’s the premise? We need to write a program that queries a user for a list of fruits. If the user says a fruit that has already been given, you say you already said that. The program should ignore casing, uppercase versus lowercase. And once 10 fruits have been given, print way to go and end the program. And so that’s fruits dot py.

[00:00:25] So you see an example here, right? “Pear, apple, pear.” “You already said that.” “Kiwi, banana, pear.” “You already said that.” “Apple.” “You already said that.” And so things to think through. We know how to write a program that queries a user for a list of fruits, for a list of anything, right? So there’s like some while true with some input and we’re going to append those inputs to a list. All right. That’s not too hard.

[00:00:49] In fact, maybe before we go much further, we could start with that shell. So let’s set up a loop where we’re going to add in all these fruits until we have 10 fruits, then we’ll deal with this middle feature next.

[00:01:08] So come over here, here’s our file. Fruits.py. Empty file, what do you just start with? Def main pass. If name is equal to main, call main. Great. So now in here, we’ve got our loop, while true, and we got our fruits. Fruit equals input fruit. Fruits dot append fruit. If length of fruits is equal to 10, break.

[00:02:01] And I guess then what do we do at the end? So we’re supposed to print it out. Way to go, right? Print way to go. Great. Now we’re done.

[00:02:14] Now we could simplify this a little bit, right? So instead of saying while true and then having this down here, in this particular situation, it would be easy enough just to say, while length of fruits is less than 10, append and append. Cool. Let’s run that.

[00:02:35] Run fruit, fruit, apple, apple, whatever. I have a pear, banana. A, a, a, a, a, a, way to go. So we can get our list of 10. And then once we have all 10 in there, finish this. Good.

[00:02:52] That wasn’t the whole program, right? What are we supposed to do? If the user says the fruit has already been given, you say, “You already said that.”

[00:03:03] So what do we want to do? We have this fruit and now we need to decide, right? If already seen, how do we know that we’ve already seen this? In this case, well, we know everything that we’ve already had, and so if the fruit you gave me is one of those, then I’m not supposed to accept it, right? How do we do that in Python? We use the in operator. So if the fruit you gave me is in the fruits already, print, “You already said that.”

[00:03:40] Otherwise we’ll take it, right? And we’ll go from there. So now we can come down here. Fruit: apple. Fruit: apple. You already said that. Pear, right? Pear, you already said that. Apple, you already said that. Great. Rather than try and think of a whole bunch of fruits, get some letters. Great. There it is.

[00:04:04] I should change that 10 to something shorter for this demonstration. Maybe we’ll go about three, make it quick. So there’s one other feature then that we wanted to keep track of, right? Right now the way this is set up, run fruits, if I give you an apple and then later an apple and an apple, it’ll take it, and we want to make it so that no matter what casing I provide, it excludes it.

[00:04:39] And the pattern typically for that is to standardize the case. So we make everything uppercase or everything lowercase, usually lowercase. So I can say you give me a fruit and then what I will do is I will just make it lowercase as it comes in. So now the input, whatever you gave me, I turned it into lowercase and then I’ll check those. And now it doesn’t matter which one you say, it’ll always print it that way.

[00:05:07] So let’s come over here. Fruit: apple. Apple. You already said that. Banana, BANANA, APPLE, pear. Cool. So the idea is it’s a very simple little program, but a few new features here to look at. One, we’ve changed the wild loop conditio. Instead of while true, we just said, while the length of fruits is less than three.

[00:05:38] Then as it grows, eventually it’ll stop. This is more similar to how we did it with bit. You can use while true with the if and a break, that’s fine. But here’s another way you can think about it.

[00:05:52] And then we talked about this idea of standardizing the case. You know, we didn’t print the fruits out. At the end, if we were to say way to go and then print out the list of fruit that was provided, you’d notice that they’re all lowercase, regardless of what we put in.

[00:06:08] And maybe that’s fine, right? If you’re building this program for somebody else, you have to go talk to them and say, hey, is it ok if I print them all out in lower case or do they need to be preserved exactly as they are? And that would add some complexity to the program.

[00:06:22] But then also here in this, we’re using the in operator for fruit and fruits as a way of checking to see if we already have a certain value. If it’s in the collection I already have, I do one thing. Otherwise, I add it to my collection. And there you go. That’s, “You already said that.”