Python for Absolute Beginners Transcripts
Chapter: Reading and writing files in Python
Lecture: Making the game extensible
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0:00
Remember how we had this dictionary
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that we were creating
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for choosing which roll was played
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and then what beats it
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and what is beaten by it, and so on?
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Like here if we play rock
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we know that rock defeats scissors
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but is defeated by or loses to paper?
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Well, look at the top here.
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If we change this where we store this
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from a source file
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into a regular file, just a data file
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like here we called it rules.json
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we can load this at startup
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and it's super easy for Python to understand
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this JSON format.
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The first thing that we're going to do
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is we're going to use a JSON file
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that looks very much like the stuff
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that we actually had built into Python.
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We're going to use this to allow
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the rules of our game to be extended
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or controlled from the outside
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without even touching the program
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or the source code or anything like that.
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Now, that might seem like overkill
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like, Well we already have it in the game file.
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Why not just leave it there?
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because, there's more variations to Rock, Paper, Scissors
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and some of them are totally awesome.
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This place at umop.com
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they've got a couple variations
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that I think are really fun.
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So here you can see at the top we have rock
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at the bottom we have paper
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and on the left we have scissors
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but now we're adding three
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no four more things.
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Fire, water, air, and sponge!
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And you can click that link in the bottom
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to learn more about it.
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So what you're going to see
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is that we could actually create this version
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of Rock, Paper, Scissors
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without touching our software
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by just changing that rules file.
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And that's going to be really cool
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because that means that people that get our game
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they could actually change the rules
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just by editing a simple text file
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and not even knowing programming.
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Sure, we could code this into there, right?
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We could actually put this one and make it a choice
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but you know what?
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There's also 25 way Rock, Paper, Scissors
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and I think there's even like 100 way Rock, Paper, Scissors.
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There's some really, really insane stuff
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so this one is really fun.
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You've got the snake, you've got the ax
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you've got the devil, you've got the wolf
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the cockroach, the alien, so.
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This one's really, really fun.
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And you can check it out at this URL here as well.
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We're not going to do this
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because it would be a lot of work
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but I do want to make a quick comment
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about the data structure stuff that we did.
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Remember our if statements
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we had three if statements.
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If it's rock, then if the other player played rock
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do something
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if they played paper, do something and so on.
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So we had nine nested if statements.
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Because there were three times three things
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and ways to play the game
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so that it ended up with nine
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but it seemed kind of bad but not terribly bad.
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If we do that with Rock, Paper, Scissors for 25 way.
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RPS-25
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we're going to end up with 625 if statements
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in a entirely non-maintainable way.
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I just want to point that out because
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this thing here would not be very hard to create an add
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to our system that we're going to create here
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either by putting it in a source code
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or this better version with a file we're going to use.
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So I think that really drives home the power
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of those data structures
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to do a much more general solution
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than to just hard coat it.
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Okay, so our first challenge is to move
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that data structure out of our program and into a file
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so that we can then extend it
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and add some of these game features to it.
