Python Forum

Is it possible to call upon a variable using other variables? For example if you have the name of a variable stored in another variable, could you call upon the first variable using the name of the variable stored in the other variable?

# The original variable
var1 = 'Z26'

var2 = 'Z'
var3 = '26'

# Is there a way to make this be equivalent to var1 = 'A1'?
var2 + var3 = 'A1'

Thanks!

It appears you want var1 to be the concatination of var2 and var3 without using any code. You are going to need some code. What are you trying to do?

I'm trying to make a chess game that will highlight the squares that the piece can play in, but to do that I need to change a variable that stores the color of the square using a variable. Here is the start of my code:

import pygame

pygame.init()
screen = pygame.display.set_mode((800,800))

pygame.display.set_caption('Chess')

x = 425
y = 325
h1 = [0,0,120]
g1 = [0,0,0]
f1 = [0,0,120]
e1 = [0,0,0]
d1 = [0,0,120]
c1 = [0,0,0]
b1 = [0,0,120]
a1 = [0,0,0]
h2 = [0,0,0]
g2 = [0,0,120]
f2 = [0,0,0]
e2 = [0,0,120]
d2 = [0,0,0]
c2 = [0,0,120]
b2 = [0,0,0]
a2 = [0,0,120]
h3 = [0,0,120]
g3 = [0,0,0]
f3 = [0,0,120]
e3 = [0,0,0]
d3 = [0,0,120]
c3 = [0,0,0]
b3 = [0,0,120]
a3 = [0,0,0]
h4 = [0,0,0]
g4 = [0,0,120]
f4 = [0,0,0]
e4 = [0,0,120]
d4 = [0,0,0]
c4 = [0,0,120]
b4 = [0,0,0]
a4 = [0,0,120]
h5 = [0,0,120]
g5 = [0,0,0]
f5 = [0,0,120]
e5 = [0,0,0]
d5 = [0,0,120]
c5 = [0,0,0]
b5 = [0,0,120]
a5 = [0,0,0]
h6 = [0,0,120]
g6 = [0,0,0]
f6 = [0,0,120]
e6 = [0,0,0]
d6 = [0,0,120]
c6 = [0,0,0]
b6 = [0,0,120]
a6 = [0,0,0]
h7 = [0,0,120]
g7 = [0,0,0]
f7 = [0,0,120]
e7 = [0,0,0]
d7 = [0,0,120]
c7 = [0,0,0]
b7 = [0,0,120]
a7 = [0,0,0]
h8 = [0,0,120]
g8 = [0,0,0]
f8 = [0,0,120]
e8 = [0,0,0]
d8 = [0,0,120]
c8 = [0,0,0]
b8 = [0,0,120]
a8 = [0,0,0]


running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    
    h1square = pygame.draw.rect(screen, (h1), pygame.Rect(0, 0, 100, 100))
    g1square = pygame.draw.rect(screen, (g1), pygame.Rect(100, 0, 100, 100))
    f1square = pygame.draw.rect(screen, (f1), pygame.Rect(200, 0, 100, 100))
    e1square = pygame.draw.rect(screen, (e1), pygame.Rect(300, 0, 100, 100))
    d1square = pygame.draw.rect(screen, (d1), pygame.Rect(400, 0, 100, 100))
    c1square = pygame.draw.rect(screen, (c1), pygame.Rect(500, 0, 100, 100))
    b1square = pygame.draw.rect(screen, (b1), pygame.Rect(600, 0, 100, 100))
    a1square = pygame.draw.rect(screen, (a1), pygame.Rect(700, 0, 100, 100))
    a2square = pygame.draw.rect(screen, (a2), pygame.Rect(700, 100, 100, 100))
    b2square = pygame.draw.rect(screen, (b2), pygame.Rect(600, 100, 100, 100))
    c2square = pygame.draw.rect(screen, (c2), pygame.Rect(500, 100, 100, 100))
    d2square = pygame.draw.rect(screen, (d2), pygame.Rect(400, 100, 100, 100))
    e2square = pygame.draw.rect(screen, (e2), pygame.Rect(300, 100, 100, 100))
    f2square = pygame.draw.rect(screen, (f2), pygame.Rect(200, 100, 100, 100))
    g2square = pygame.draw.rect(screen, (g2), pygame.Rect(100, 100, 100, 100))
    h2square = pygame.draw.rect(screen, (h2), pygame.Rect(0, 100, 100, 100))
    h3square = pygame.draw.rect(screen, (h3), pygame.Rect(0, 200, 100, 100))
    g3square = pygame.draw.rect(screen, (g3), pygame.Rect(100, 200, 100, 100))
    f3square = pygame.draw.rect(screen, (f3), pygame.Rect(200, 200, 100, 100))
    e3square = pygame.draw.rect(screen, (e3), pygame.Rect(300, 200, 100, 100))
    d3square = pygame.draw.rect(screen, (d3), pygame.Rect(400, 200, 100, 100))
    c3square = pygame.draw.rect(screen, (c3), pygame.Rect(500, 200, 100, 100))
    b3square = pygame.draw.rect(screen, (b3), pygame.Rect(600, 200, 100, 100))
    a3square = pygame.draw.rect(screen, (a3), pygame.Rect(700, 200, 100, 100))
    a4square = pygame.draw.rect(screen, (a4), pygame.Rect(700, 300, 100, 100))
    b4square = pygame.draw.rect(screen, (b4), pygame.Rect(600, 300, 100, 100))
    c4square = pygame.draw.rect(screen, (c4), pygame.Rect(500, 300, 100, 100))
    d4square = pygame.draw.rect(screen, (d4), pygame.Rect(400, 300, 100, 100))
    e4square = pygame.draw.rect(screen, (e4), pygame.Rect(300, 300, 100, 100))
    f4square = pygame.draw.rect(screen, (f4), pygame.Rect(200, 300, 100, 100))
    g4square = pygame.draw.rect(screen, (g4), pygame.Rect(100, 300, 100, 100))
    h4square = pygame.draw.rect(screen, (h4), pygame.Rect(0, 300, 100, 100))
    h5square = pygame.draw.rect(screen, (h5), pygame.Rect(0, 400, 100, 100))
    g5square = pygame.draw.rect(screen, (g5), pygame.Rect(100, 400, 100, 100))
    f5square = pygame.draw.rect(screen, (f5), pygame.Rect(200, 400, 100, 100))
    e5square = pygame.draw.rect(screen, (e5), pygame.Rect(300, 400, 100, 100))
    d5square = pygame.draw.rect(screen, (d5), pygame.Rect(400, 400, 100, 100))
    c5square = pygame.draw.rect(screen, (c5), pygame.Rect(500, 400, 100, 100))
    b5square = pygame.draw.rect(screen, (b5), pygame.Rect(600, 400, 100, 100))
    a5square = pygame.draw.rect(screen, (a5), pygame.Rect(700, 400, 100, 100))
    h6square = pygame.draw.rect(screen, (h6), pygame.Rect(700, 500, 100, 100))
    g6square = pygame.draw.rect(screen, (g6), pygame.Rect(600, 500, 100, 100))
    f6square = pygame.draw.rect(screen, (f6), pygame.Rect(500, 500, 100, 100))
    e6square = pygame.draw.rect(screen, (e6), pygame.Rect(400, 500, 100, 100))
    d6square = pygame.draw.rect(screen, (d6), pygame.Rect(300, 500, 100, 100))
    c6square = pygame.draw.rect(screen, (c6), pygame.Rect(200, 500, 100, 100))
    b6square = pygame.draw.rect(screen, (b6), pygame.Rect(100, 500, 100, 100))
    a6square = pygame.draw.rect(screen, (a6), pygame.Rect(0, 500, 100, 100))
    h7square = pygame.draw.rect(screen, (h7), pygame.Rect(0, 600, 100, 100))
    g7square = pygame.draw.rect(screen, (g7), pygame.Rect(100, 600, 100, 100))
    f7square = pygame.draw.rect(screen, (f7), pygame.Rect(200, 600, 100, 100))
    e7square = pygame.draw.rect(screen, (e7), pygame.Rect(300, 600, 100, 100))
    d7square = pygame.draw.rect(screen, (d7), pygame.Rect(400, 600, 100, 100))
    c7square = pygame.draw.rect(screen, (c7), pygame.Rect(500, 600, 100, 100))
    b7square = pygame.draw.rect(screen, (b7), pygame.Rect(600, 600, 100, 100))
    a7square = pygame.draw.rect(screen, (a7), pygame.Rect(700, 600, 100, 100))
    h8square = pygame.draw.rect(screen, (h8), pygame.Rect(700, 700, 100, 100))
    g8square = pygame.draw.rect(screen, (g8), pygame.Rect(600, 700, 100, 100))
    f8square = pygame.draw.rect(screen, (f8), pygame.Rect(500, 700, 100, 100))
    e8square = pygame.draw.rect(screen, (e8), pygame.Rect(400, 700, 100, 100))
    d8square = pygame.draw.rect(screen, (d8), pygame.Rect(300, 700, 100, 100))
    c8square = pygame.draw.rect(screen, (c8), pygame.Rect(200, 700, 100, 100))
    b8square = pygame.draw.rect(screen, (b8), pygame.Rect(100, 700, 100, 100))
    a8square = pygame.draw.rect(screen, (a8), pygame.Rect(0, 700, 100, 100))

    pawn1 = pygame.draw.rect(screen, (255,255,255), pygame.Rect(x, y, 50, 50))

    pos = pygame.mouse.get_pos()
    pressed1, pressed2, pressed3 = pygame.mouse.get_pressed()
    if pawn1.collidepoint(pos) and pressed1:
        coords = pygame.mouse.get_pos()
        xcoord = coords[0] / 100
        ycoord = coords[1] / 100
                
        if ycoord > 7:
            ycoord = "8"
        elif 6 < ycoord < 7:
            ycoord = "7"
        elif 5 < ycoord < 6:
            ycoord = "6"
        elif 4 < ycoord < 5:
            ycoord = "5"
        elif 3 < ycoord < 4:
            ycoord = "4"
        elif 2 < ycoord < 3:
            ycoord = "3"
        elif 1 < ycoord < 2:
            ycoord = "2"
        elif ycoord < 1:
            ycoord = "1"

        if xcoord > 7:
            xcoord = "a"
        elif 6 < xcoord < 7:
            xcoord = "b"
        elif 5 < xcoord < 6:
            xcoord = "c"
        elif 4 < xcoord < 5:
            xcoord = "d"
        elif 3 < xcoord < 4:
            xcoord = "e"
        elif 2 < xcoord < 3:
            xcoord = "f"
        elif 1 < xcoord < 2:
            xcoord = "g"
        elif xcoord < 1:
            xcoord = "h"

        upto = int(ycoord) + 1
        print(xcoord + str(upto))
        xcoord + str(upto) = var
        var = [255,255,255]
        
            
    pygame.display.update()

Using this code I can get the name of the square that the pawn is in, but to do anything with that I have to call upon a variable using this. Thanks!

Instead of using a variable to store the color you could use a function that returns the color. As I said, somewhere you need code.

Your code is odd. I don't have any pygame experience at all, but I think you would want to some sort of collection object instead of having a named variable for each thing. Since the squares on the board are an important part of the game I might make a class to hold all the information for a square such as the location, the background color, and any chess piece landing on the square:

class Square():
    '''A location on the board'''
    def __init__(self, rank, file):
        self.rank = rank
        self.file = file
        self.name = 'abcdefgh'[rank]+str(file+1)
        self.background = [0,0,120] if (rank+file)%2 else [0,0,0]
        x = (rank)*100  # Not sure of pygame coordinates so this could be wrong
        y = (file)*100
        self.rectangle = [x, y, 100, 100]
        self.occupant = None

    def draw(self):
        '''Draw self on screen'''
        self.square = pygame.draw.rect(screen, self.color, self.rectangle)
        if self.occupant:
            '''Draw image for piece occupying square'''

    @property
    def piece(self):
        '''Return occupant'''
        return self.occupant

    @piece.setter
    def place(self, piece):
       '''Set the occupant.  Redraw the square'''
        self.occupant = piece
        self.draw()

In addition to storing information a class can also have actions. My Square class would have an action (method) to draw the square and another for adding or removing a chess piece. I might make the latter a property so I can use the same property to see or set what piece occupies a square.

The board is just a collection of squares, so I make a class that represents that.

class Board():
    '''A grid of Squares'''
    def __init__(self):
        self.ranks = []
        for rank in range(8):
            self.rank.append([Square(rank, file) for file in range(8)])

    def square(self, rank, file):
        """Return square at rank/file"""
        return self.rank[rank][file]

    def move(self, r1, f1, r2, f2):
        '''Move piece from r1, f1 to r2, f2'''
        self.square(r2, f2).piece = self.square(r1, f1).piece
        self.square(r1, f1).piece = None

    def draw(self):
        '''Draw the board'''
        for rank in self.ranks:
            for square in rank:
                square.draw()

Now I can make and draw a chess board in two lines:

board = Board()
board.draw()

And I can move a piece in one line

board.move(startRank, startFile, endRank, endFile)

Thanks, I think I can get this working now!