代码行 if board [i][j]==0 是做什么的？

Question

所以我在网上找到了这段代码，因为我想制作自己的代码，所以我想通过查看所有不同行的作用来理解这个人在做什么，但我遇到了这条线，但我不知道它能做什么。我真的无法在网上找到任何东西，主要是因为我不知道如何查找它或它叫什么。这是来自游戏 connect 4 的一段代码，这是绘制圆圈的函数。我说的是

if board[i][j]==0:

和

if board[i][j]==1:

代码。它在这个小函数中：

def draw_pieces(): #draws the pieces
    global board #makes 'board' global
    row_gap = HEIGHT/ROWS #variable row_gap is now 771,4 / 6 = 128,6 (gap between circles)
    col_gap = WIDTH/COLS #variable col_gap is now 900 / 7 = 128,6 (gap between circles)
    Y = STARTY + row_gap / 2; # Y is now -385,7 + 128,6 / 2 = -321,4 
    for i in range(ROWS): #this next function happens 6 times (i think its first black their turn)
        X = STARTX + col_gap/2 #X is now -450 + 128,6 / 2 = -385,7
        for j in range(COLS): #this next function happens 7 times (then red their turn)
            if board[i][j] == 0: #if board i and j are equal to 0??
                draw_circle(X,Y,row_gap/3,'white') #draw a circle on X and Y, radius row_gap/3 and in color white
            elif board[i][j] == 1: #if board i and j are equal to 1??
                draw_circle(X,Y,row_gap/3,'black') #draw a circle on X and Y, raduis row_gap/3 and in color black
            else: #if board i and j are equal to anything else??
                draw_circle(X,Y,row_gap/3,'red') #draw a circle on X and Y, radius row_gao/3 and in color red
            X += col_gap #for every j, X is now added with col_gap (128,6)
        Y += row_gap #for every i, Y is now added with row_gap (128,6)

请原谅我对每一行的所有评论，我正在努力理解代码。如果有人可以帮助我（或分享解释它的网站或文档），将不胜感激！

Answer 1

如果我们查看 source and illustration of this game from pythonturtle.academy，我们可以更清楚地看到代码的作用：

二维 board 矩阵存储三个值之一，0 表示 'white' 或未占用，1 表示 'black'，第 1 个玩家，2 表示 'red'，第二名球员。所以有问题的代码是在板上绘制圆圈，其颜色基于谁占据（或不占据）行和列，[i][j]，问题：

if board[i][j] == 0:
    draw_circle(X,Y,row_gap/3,'white')
elif board[i][j] == 1:
    draw_circle(X,Y,row_gap/3,'black')
else:
    draw_circle(X,Y,row_gap/3,'red')

else: 子句是隐含的 elif board[i][j] == 2:

代码行 if board [i][j]==0 是做什么的？

What does the code line if board [i][j]==0 do?

python

turtle-graphics

python-turtle