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Well done!
You have completed Basic Object-Oriented Python!
You have completed Basic Object-Oriented Python!
Preview
Start writing the logic for the game class for our memory game.
Accomplished in this Video
- Created a Game class
- created instances attributes
- size
- card_options = words
- column names
- list to hold our cards
- all grid locations
- Created our cards
- Used
randomand sets to get random locations for each card - created the Card instance and saved it to our card list
- Used
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Time to tackle the game class.
0:00
Let's do this.
0:02
As always, we'll start with a class and
let's call it Game.
0:04
Then add an init method.
0:14
And inside, set the size attribute
that holds the size of our grid to 4.
0:20
Then let's create our card_options
with a list of words.
0:35
A bit of math here.
0:46
If our grid size is 4,
that means we're creating a 4 by 4 grid,
0:47
which means there will
be 16 cards in our grid.
0:53
And since we're matching cards,
0:58
we only need eight options
because 8 times 2 is 16.
1:01
It's also best to make sure
each word is the same length so
1:06
your grid is nicely laid
out in the console.
1:11
I stuck with three letter words, but
1:14
feel free to add whatever words you want
as long as they're all the same length.
1:16
And since this is getting a bit long,
I'm going to split it onto two lines.
1:47
Next, let's create a list
of the column names.
2:01
Since our size is 4,
we need four column names.
2:04
A, B, C, and D will work just fine.
2:09
Then we'll need to create an empty list
to eventually hold our card instances for
2:28
the game when we create them.
2:33
We'll create each card and then append
it to this list for use in our game.
2:38
Lastly, we'll need to get a list
of locations in our grid.
2:44
Let's create an empty list first.
2:48
Now we're going to loop
through our columns and
2:54
rows to create all the possible locations
in our grid to add to our list.
2:57
The locations will be A1, B1, C1,
3:03
D1, A2, B2, and so on.
3:08
First, create a for
loop to loop through each column.
3:12
Then we'll need to loop
through a range from 1 to 4.
3:22
Remember, range can take a start,
stop, and step parameters.
3:28
The only one that is required is the stop.
3:39
Python will automatically start at zero
and step by one if they are not stated.
3:43
The stop number is also not
included in the given range.
3:49
For example,
3:56
If we print out each number in a range
of 3, we get the numbers 0,1, and 2.
4:09
If we need our range to create
4:16
the numbers 1, 2, 3, and 4,
what should the range look like?
4:18
Take a quick minute to figure that out.
4:24
For num in starting at 1 and
4:29
ending at 5, which is our
4:35
self.size of our grid plus 1.
4:41
Let's print out what we've got so far to
the console so we can see what's going on.
4:48
Don't forget to create an instance.
5:22
Run the file.
5:43
Cool, we're getting B1, 2,
3, 4, C1, 2, and so on.
5:48
We're getting our 16 locations.
5:54
Now we need to append them to our list.
5:56
Nice, our init is all set.
6:15
Now let's tackle creating the cards.
6:18
We have our words, and
we now have the locations.
6:21
So let's put them together
using our card class.
6:25
First, we need to import our
6:28
card class so we can use it.
6:30
From cards import Card.
6:40
We're also going to need random so
we can get random locations for each card.
6:46
Otherwise, they would all be laid out
in the same pattern every time and
6:55
the game wouldn't be that much fun.
7:00
Now let's add a method called set_cards.
7:03
It won't take any arguments so
we only need self here.
7:25
Now when we give a card a random location,
we can't use that location again.
7:36
There's a few ways you can do this, but
7:43
I went with creating an empty
list called used_locations.
7:46
This will hold the locations that
have been used for reference.
7:52
Now to create the cards, we need to
loop through our card_options so
7:57
we create cards for each word.
8:02
Then we'll also need to loop again,
so that we create
8:11
two cards for every word so
we get our full 16 cards.
8:16
To do this, we can use range(2) and
the variable i.
8:21
Since it's just a placeholder,
we don't actually need it.
8:26
Cool, now that we're set up to grab
a card and then do something twice,
8:35
let's add the logic to grab a location and
create and append our card.
8:40
First, let's grab a random location.
8:46
Now in Python, we have a structure
that allows us to remove duplicates.
8:49
They're called sets.
8:54
Sets look kind of like a list, but
they use curly brackets instead.
9:00
If I subtract one set from another,
9:13
I am left with only the values
that are not duplicates.
9:16
a is in both sets, so
when I subtract them,
9:22
the duplicate is removed,
leaving us only with b.
9:26
We can use this by converting
our two lists, locations and
9:36
used_locations, into sets and
subtracting them.
9:41
We'll then end up with only locations
that haven't been used because it
9:45
removes the duplicates.
9:50
Now I'm going to convert it back into
a list so we can use random on it.
10:11
This works because subtracting
the sets removes the duplicates,
10:31
leaving us only with
locations that are available.
10:36
And then we get to randomly choose one.
10:40
We'll need to now append
this random_location to
10:43
our used_locations since it's now,
well, used.
10:48
Now we can finally create
our card instance.
11:00
Pass in the word and its location, and
then append it to our games cards list.
11:03
Let's do some printing to test this out.
11:30
Now before I show you, pause me and
try testing this out on your own.
11:33
How can you check to make sure we have
16 cards that are eight different
11:39
words with 16 different locations?
11:44
Here's one way to test it out.
11:54
Make this a variable, call our set_cards
11:58
method so the cards get created.
12:03
And then do a for loop so
that you can see each of your cards.
12:07
Now let's run the file.
12:17
And, oops,
looks like I forgot a self, line 19
12:21
Can't forget that self.
12:35
Okay, now let's give it a try.
12:40
And great,
we have all of our words in pairs.
12:48
We've done a lot so far.
12:56
Take a minute and reread the code,
make sure you know what is happening.
12:59
And if you don't, that's okay.
13:03
Re-watch the video or play around
with the code by testing it out.
13:06
Sometimes it helps to talk
through the code out loud.
13:11
It's called the rubber ducky method.
13:15
There's also a great
community here ready to help.
13:18
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