CODEWITHSUNDEEP
pythonlist-comprehension
SamChancer
SamChancer

Reputation: 75

Python: List comprehension into an x,y list

I am working with two ranges to place tiles in a 2d game, so I've created a 'tilemap'...

tilemap = [ [TILE for w in range(MAPWIDTH)] for h in range(MAPWIDTH)]

this works... now I want to attach instances of a class called 'piecemap' that corresponds to the tilemap. To do this I have a class called Piece that looks like this...

class Piece():
   otherstuff = "string"
   location = [0,0]

My question is how can I load the "w" in width range and the "h" in height range into the "location" attribute using list comprehension? Currently my effort (that doesn't work) looks like this...

piecemap = [[Piece.location[0] for w in range(MAPWIDTH)],[Piece.location[1] for h in range(MAPHEIGHT)]

I know it's wrong but no idea how to make it right! any help?

Upvotes: 3

Views: 873

Answers (5)

Pynchia
Pynchia

Reputation: 11590

From what I read, I assume the location is an attribute of each Piece instance (not a class attribute). The same goes for the name attribute (maybe). Therefore, I would set the location when creating such objects:

class Piece():
    otherstuff = "string"
    def __init__(self,x,y):
        self.location = [x, y]
        # self.otherstuff = name # add it to the parameters if that's the case

piecemap = [[Piece(w,h) for h in range(MAPWIDTH)] for w in range(MAPHEIGHT)]

Upvotes: 2

Eugene Soldatov
Eugene Soldatov

Reputation: 10135

I don't know for what you need Piece class, but you can retrieve all locations using zip function:

piecemap = zip(range(MAPWIDTH), range(MAPHEIGHT))

Upvotes: 1

Robᵩ
Robᵩ

Reputation: 168616

class Piece():
   otherstuff = "string"
   location = [0,0]

That is a very odd-looking class. You have class attributes otherstuff and location, as if every Piece ever created would occupy the same location.

Rather, you probably want instance attributes, like so:

class Piece:
    def __init__(self, x, y, name="Unspecified"):
        self.location = [x,y]
        self.otherstuff = name

Then your list comprehension looks like:

tilemap = [ [Piece(w, h) for w in range(MAPWIDTH)] for h in range(MAPWIDTH)]

Upvotes: 5

mikeb
mikeb

Reputation: 11267

Don't you want something like this:

tilemap = [ (w, h) for w in range(MAPWIDTH) for h in range(MAPWIDTH)]

MAPWIDTH = 3

[(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)

Then you can create your "Piece" objects?

Upvotes: 1

Sergius
Sergius

Reputation: 986

You need something like this:

>>> [[x,y] for x in range(3) for y in range(2)]
[[0, 0], [0, 1], [1, 0], [1, 1], [2, 0], [2, 1]]

In your case it probably:

piecemap = [[Piece.location[0], Piece.location[1]] for w in range(MAPWIDTH)] for h in range(MAPHEIGHT)]

But I'm not sure what you're really expecting

Upvotes: 1

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