Python for Absolute Beginners Transcripts
Chapter: Organizing and reusing code with functions
Lecture: A function for winning
Login or
purchase this course
to watch this video and the rest of the course contents.
0:00
Well, the first part
0:01
of our play game is much, much nicer.
0:03
This line 22, get the roll validated from the player.
0:06
And it gets us a chance
0:07
to get out of here if that doesn't work.
0:09
This other part of checking for a winner
0:12
makes up a ton of stuff over here.
0:15
So all the way, this reporting
0:17
this is not really getting the winner
0:19
this is more about reporting who won.
0:21
But from here all the way to there
0:25
that blue bit, that is the code
0:27
along with a comment that we wrote, to get the winner.
0:30
So what we've done so far, is we've gone and said
0:32
Okay, well let's make a function.
0:33
I'm going to go type def, a thing I want to call it.
0:35
Figure out parameters go in there, what gets returned.
0:38
And it's very manual.
0:39
And you need to be able to do that.
0:41
You need to do enough practice
0:42
so that that makes a lot of sense for you.
0:45
But once you get used to it, you can leverage tools
0:47
like PyCharm, to make this much more error free.
0:50
Okay, down here, remember, in this section
0:53
I said, I want to rename roll.
0:55
So I'm going to use this refactor idea
0:56
to make sure that PyCharm can verify every bit
0:59
where we're using roll, roll one.
1:02
If we want to rename that
1:03
we do that in a consistent and valid way.
1:05
But with functions, we can do that even better.
1:07
So watch this.
1:08
So I want to take all of this and that winner and test.
1:11
So let's look through that process again.
1:13
So it's going to take roll one and roll two
1:15
it needs that information.
1:16
It needs to know player_1 and player_2.
1:20
And then it has to give back the winner
1:21
so the winner can be used here.
1:23
So watch this.
1:24
Don't have to use this tool
1:26
but it's super cool to help you
1:27
when you're getting started or when you're a professional.
1:30
It'll be good for a long time.
1:31
So extract method
1:33
this means take all this code I've highlighted
1:35
and create a function.
1:37
Give it everything it needs to get started
1:38
and return what it needs to return.
1:40
Beware, this doesn't always work.
1:42
Sometimes things are too complicated
1:44
to make sense to do this automatically.
1:46
So, let's see what we get.
1:48
So it says we're going to have a extract.
1:50
Extract method is going to need a name
1:52
this is the name we want to call the function.
1:54
We'll say, check_for_winning_throw.
1:56
And notice, it says it takes player_1, player_2
1:58
roll one, and roll two as you would expect there.
2:02
And let's make this a little taller.
2:03
It's kind of weird, the way it's getting squooshed.
2:06
Well, whatever.
2:07
It doesn't want to resize.
2:08
So then notice the output variable is winner.
2:10
And if I hit okay, watch this.
2:12
Boom, all that stuff, all those complicated lines
2:16
are reduced down to this.
2:17
check_for_winning_throw.
2:19
Give it player_1, player_2, and roll one, and roll two.
2:21
And then it's going to come back and do the same test
2:24
with the data, here, that is returned.
2:26
And then down here
2:27
this is the thing that was created for us.
2:29
Right?
2:30
All this code down here was written by PyCharm
2:32
when we said extract method.
2:34
So that's pretty cool, right?
2:36
We could leave this comment up here.
2:37
Probably this check for winner
2:38
test for winner, is not necessary
2:40
because check for winning throw already tells us.
2:43
We could leave these comments here
2:44
if we think they're going to be helpful
2:46
probably they are for now.
2:47
So let's just leave that.
2:48
Now, we've changed our code in a way that's way cleaner
2:51
like hide that away, hide that away.
2:53
Now we can look at this and we can say
2:55
Okay, what does our program do?
2:56
Choose the header, comes up with the two players
2:59
and it plays the game. And we could actually do this as well.
3:02
We come down here and just write in place, you and computer.
3:06
Like that.
3:07
And we don't even have to explicitly do that.
3:10
So we're going to show the header and play the game.
3:12
Play game is made up of getting the rules
3:14
and getting the rule validated from the player.
3:16
If you can't play, you can't play.
3:18
We have this little print out, so we know what's happening.
3:20
And then we check for a winner.
3:21
It doesn't matter how complicated that is.
3:23
As we'll see, it can get more complicated
3:25
or better as we work on it.
3:27
And then the game is over
3:28
depending on how many people have won.
3:30
Let's try that.
3:31
It should behave exactly the same
3:33
but it is much easier to think about.
3:34
And you'll see that it's also easier for us to add
3:37
the best of five, or best of three, or whatever.
3:40
I'm going to play rock.
3:41
I threw a rock, paper throws rock.
3:43
The game was tied.
3:44
So look, it still works, just like it should have.
3:47
Let's do one more.
3:48
Scissors, you roll scissors.
3:49
Computer rolls scissors.
3:50
Now the computer rolls rock.
3:52
Game over.
3:54
Ah, we lost. But we won the game of programming, didn't we?
3:57
Look at this. Look how much nicer this is.
3:59
And if we need to check for winning in other places
4:02
or we need to get rolls in other places
4:04
we just do that one line again.
4:06
And it allows us to have a simpler code
4:09
that we think in high levels about
4:10
but also to reuse it.
4:12
'Cause if you want to call it again
4:13
there's your player_2 against player_1 in a manual way.
4:17
Right? If you wanted to play computer
4:18
we could just come down here.
4:19
And I play rock, they play paper, boom, that's it.
4:23
Look how easy it was for us
4:25
to convert from an automatic player
4:27
over to one where we have a multi-player sort of situation.
4:31
And that was easy because this code is incredibly reusable.
4:35
All we got to do is call the function again
4:37
with different inputs, boom, we're off to the races.
